Document Framebuffer Filters, VisCvg and VisZbuf (#1534)

* Document z_viscvg and z_viszbuf

Co-authored-by: Tharo <17233964+Thar0@users.noreply.github.com>
Co-authored-by: Dragorn421 <Dragorn421@users.noreply.github.com>

* Few more notes

* Some more notes

Co-authored-by: Tharo <17233964+Thar0@users.noreply.github.com>

* Review

* Americanisation, FB RGB

* Oops

* Review

* Minor documentation modifications

* Header, base struct and enums

Co-authored-by: Tharo <17233964+Thar0@users.noreply.github.com>

* functions.h fix

* Suggested changes, further adjustments to file doc comments

* Further suggested changes, standardize capitalization of gfxP

* g

---------

Co-authored-by: Elliptic Ellipsis <elliptic.ellipsis@gmail.com>
Co-authored-by: Dragorn421 <Dragorn421@users.noreply.github.com>

15 files changed, 427 insertions, 317 deletions

diff --git a/src/code/PreRender.c b/src/code/PreRender.c
index 0a1b0f2cf..fb40f6e38 100644
--- a/src/code/PreRender.c
+++ b/src/code/PreRender.c
@@ -43,19 +43,19 @@ void PreRender_Destroy(PreRender* this) {
 /**
  * Copies RGBA16 image `img` to `imgDst`
  *
- * @param gfxp      Display list pointer
+ * @param gfxP      Display list pointer
  * @param img       Image to copy from
  * @param imgDst    Buffer to copy to
  */
-void PreRender_CopyImage(PreRender* this, Gfx** gfxp, void* img, void* imgDst) {
+void PreRender_CopyImage(PreRender* this, Gfx** gfxP, void* img, void* imgDst) {
     Gfx* gfx;
     s32 rowsRemaining;
     s32 curRow;
     s32 nRows;
 
     LogUtils_CheckNullPointer("this", this, "../PreRender.c", 215);
-    LogUtils_CheckNullPointer("glistpp", gfxp, "../PreRender.c", 216);
-    gfx = *gfxp;
+    LogUtils_CheckNullPointer("glistpp", gfxP, "../PreRender.c", 216);
+    gfx = *gfxP;
     LogUtils_CheckNullPointer("glistp", gfx, "../PreRender.c", 218);
 
     gDPPipeSync(gfx++);
@@ -101,22 +101,22 @@ void PreRender_CopyImage(PreRender* this, Gfx** gfxp, void* img, void* imgDst) {
 
     gDPPipeSync(gfx++);
     gDPSetColorImage(gfx++, G_IM_FMT_RGBA, G_IM_SIZ_16b, this->width, this->fbuf);
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
 /**
  * Copies part of `this->fbufSave` in the region (this->ulx, this->uly), (this->lrx, this->lry) to the same location in
  * `this->fbuf`.
  */
-void PreRender_CopyImageRegionImpl(PreRender* this, Gfx** gfxp) {
+void PreRender_CopyImageRegionImpl(PreRender* this, Gfx** gfxP) {
     Gfx* gfx;
     s32 rowsRemaining;
     s32 curRow;
     s32 nRows;
 
     LogUtils_CheckNullPointer("this", this, "../PreRender.c", 278);
-    LogUtils_CheckNullPointer("glistpp", gfxp, "../PreRender.c", 279);
-    gfx = *gfxp;
+    LogUtils_CheckNullPointer("glistpp", gfxP, "../PreRender.c", 279);
+    gfx = *gfxP;
     LogUtils_CheckNullPointer("glistp", gfx, "../PreRender.c", 281);
 
     gDPPipeSync(gfx++);
@@ -164,22 +164,22 @@ void PreRender_CopyImageRegionImpl(PreRender* this, Gfx** gfxp) {
     gDPPipeSync(gfx++);
     gDPSetColorImage(gfx++, G_IM_FMT_RGBA, G_IM_SIZ_16b, this->width, this->fbuf);
     gDPSetScissor(gfx++, G_SC_NON_INTERLACE, 0, 0, this->width, this->height);
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
 /**
  * Copies `buf` to `bufSave`, discarding the alpha channel and modulating the RGB channel by
  * the color ('r', 'g', 'b', 'a')
  */
-void func_800C170C(PreRender* this, Gfx** gfxp, void* buf, void* bufSave, u32 r, u32 g, u32 b, u32 a) {
+void func_800C170C(PreRender* this, Gfx** gfxP, void* buf, void* bufSave, u32 r, u32 g, u32 b, u32 a) {
     Gfx* gfx;
     s32 rowsRemaining;
     s32 curRow;
     s32 nRows;
 
     LogUtils_CheckNullPointer("this", this, "../PreRender.c", 343);
-    LogUtils_CheckNullPointer("glistpp", gfxp, "../PreRender.c", 344);
-    gfx = *gfxp;
+    LogUtils_CheckNullPointer("glistpp", gfxP, "../PreRender.c", 344);
+    gfx = *gfxP;
     LogUtils_CheckNullPointer("glistp", gfx, "../PreRender.c", 346);
 
     gDPPipeSync(gfx++);
@@ -232,33 +232,33 @@ void func_800C170C(PreRender* this, Gfx** gfxp, void* buf, void* bufSave, u32 r,
 
     gDPPipeSync(gfx++);
     gDPSetColorImage(gfx++, G_IM_FMT_RGBA, G_IM_SIZ_16b, this->width, this->fbuf);
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
 /**
  * Copies `fbuf` to `fbufSave`, discarding the alpha channel and leaving the rgb channel unchanged
  */
-void func_800C1AE8(PreRender* this, Gfx** gfxp, void* fbuf, void* fbufSave) {
-    func_800C170C(this, gfxp, fbuf, fbufSave, 255, 255, 255, 255);
+void func_800C1AE8(PreRender* this, Gfx** gfxP, void* fbuf, void* fbufSave) {
+    func_800C170C(this, gfxP, fbuf, fbufSave, 255, 255, 255, 255);
 }
 
 /**
  * Reads the coverage values stored in the RGBA16 format `img` with dimensions `this->width`, `this->height` and
  * converts it to an 8-bpp intensity image.
  *
- * @param gfxp      Display list pointer
+ * @param gfxP      Display list pointer
  * @param img       Image to read coverage from
  * @param cvgDst    Buffer to store coverage into
  */
-void PreRender_CoverageRgba16ToI8(PreRender* this, Gfx** gfxp, void* img, void* cvgDst) {
+void PreRender_CoverageRgba16ToI8(PreRender* this, Gfx** gfxP, void* img, void* cvgDst) {
     Gfx* gfx;
     s32 rowsRemaining;
     s32 curRow;
     s32 nRows;
 
     LogUtils_CheckNullPointer("this", this, "../PreRender.c", 422);
-    LogUtils_CheckNullPointer("glistpp", gfxp, "../PreRender.c", 423);
-    gfx = *gfxp;
+    LogUtils_CheckNullPointer("glistpp", gfxP, "../PreRender.c", 423);
+    gfx = *gfxP;
     LogUtils_CheckNullPointer("glistp", gfx, "../PreRender.c", 425);
 
     gDPPipeSync(gfx++);
@@ -326,30 +326,30 @@ void PreRender_CoverageRgba16ToI8(PreRender* this, Gfx** gfxp, void* img, void*
     // Reset the color image to the current framebuffer
     gDPPipeSync(gfx++);
     gDPSetColorImage(gfx++, G_IM_FMT_RGBA, G_IM_SIZ_16b, this->width, this->fbuf);
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
 /**
  * Saves zbuf to zbufSave
  */
-void PreRender_SaveZBuffer(PreRender* this, Gfx** gfxp) {
+void PreRender_SaveZBuffer(PreRender* this, Gfx** gfxP) {
     LogUtils_CheckNullPointer("this->zbuf_save", this->zbufSave, "../PreRender.c", 481);
     LogUtils_CheckNullPointer("this->zbuf", this->zbuf, "../PreRender.c", 482);
 
     if ((this->zbufSave != NULL) && (this->zbuf != NULL)) {
-        PreRender_CopyImage(this, gfxp, this->zbuf, this->zbufSave);
+        PreRender_CopyImage(this, gfxP, this->zbuf, this->zbufSave);
     }
 }
 
 /**
  * Saves fbuf to fbufSave
  */
-void PreRender_SaveFramebuffer(PreRender* this, Gfx** gfxp) {
+void PreRender_SaveFramebuffer(PreRender* this, Gfx** gfxP) {
     LogUtils_CheckNullPointer("this->fbuf_save", this->fbufSave, "../PreRender.c", 495);
     LogUtils_CheckNullPointer("this->fbuf", this->fbuf, "../PreRender.c", 496);
 
     if ((this->fbufSave != NULL) && (this->fbuf != NULL)) {
-        func_800C1AE8(this, gfxp, this->fbuf, this->fbufSave);
+        func_800C1AE8(this, gfxP, this->fbuf, this->fbufSave);
     }
 }
 
@@ -357,8 +357,8 @@ void PreRender_SaveFramebuffer(PreRender* this, Gfx** gfxp) {
  * Fetches the coverage of the current framebuffer into an image of the same format as the current color image, storing
  * it over the framebuffer in memory.
  */
-void PreRender_FetchFbufCoverage(PreRender* this, Gfx** gfxp) {
-    Gfx* gfx = *gfxp;
+void PreRender_FetchFbufCoverage(PreRender* this, Gfx** gfxP) {
+    Gfx* gfx = *gfxP;
 
     gDPPipeSync(gfx++);
     // Set the blend color to full white and set maximum depth.
@@ -392,33 +392,33 @@ void PreRender_FetchFbufCoverage(PreRender* this, Gfx** gfxp) {
     gDPFillRectangle(gfx++, 0, 0, this->width, this->height);
     gDPPipeSync(gfx++);
 
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
 /**
  * Draws the coverage of the current framebuffer `this->fbuf` to an I8 image at `this->cvgSave`. Overwrites
  * `this->fbuf` in the process.
  */
-void PreRender_DrawCoverage(PreRender* this, Gfx** gfxp) {
-    PreRender_FetchFbufCoverage(this, gfxp);
+void PreRender_DrawCoverage(PreRender* this, Gfx** gfxP) {
+    PreRender_FetchFbufCoverage(this, gfxP);
     LogUtils_CheckNullPointer("this->cvg_save", this->cvgSave, "../PreRender.c", 532);
     if (this->cvgSave != NULL) {
-        PreRender_CoverageRgba16ToI8(this, gfxp, this->fbuf, this->cvgSave);
+        PreRender_CoverageRgba16ToI8(this, gfxP, this->fbuf, this->cvgSave);
     }
 }
 
 /**
  * Restores zbufSave to zbuf
  */
-void PreRender_RestoreZBuffer(PreRender* this, Gfx** gfxp) {
-    PreRender_CopyImage(this, gfxp, this->zbufSave, this->zbuf);
+void PreRender_RestoreZBuffer(PreRender* this, Gfx** gfxP) {
+    PreRender_CopyImage(this, gfxP, this->zbufSave, this->zbuf);
 }
 
 /**
  * Draws a full-screen image to the current framebuffer, that sources the rgb channel from `this->fbufSave` and
  * the alpha channel from `this->cvgSave` modulated by environment color.
  */
-void func_800C213C(PreRender* this, Gfx** gfxp) {
+void func_800C213C(PreRender* this, Gfx** gfxP) {
     Gfx* gfx;
     s32 rowsRemaining;
     s32 curRow;
@@ -427,8 +427,8 @@ void func_800C213C(PreRender* this, Gfx** gfxp) {
 
     if (this->cvgSave != NULL) {
         LogUtils_CheckNullPointer("this", this, "../PreRender.c", 563);
-        LogUtils_CheckNullPointer("glistpp", gfxp, "../PreRender.c", 564);
-        gfx = *gfxp;
+        LogUtils_CheckNullPointer("glistpp", gfxP, "../PreRender.c", 564);
+        gfx = *gfxP;
         LogUtils_CheckNullPointer("glistp", gfx, "../PreRender.c", 566);
 
         gDPPipeSync(gfx++);
@@ -482,23 +482,23 @@ void func_800C213C(PreRender* this, Gfx** gfxp) {
         }
 
         gDPPipeSync(gfx++);
-        *gfxp = gfx;
+        *gfxP = gfx;
     }
 }
 
 /**
  * Copies fbufSave to fbuf
  */
-void PreRender_RestoreFramebuffer(PreRender* this, Gfx** gfxp) {
-    PreRender_CopyImage(this, gfxp, this->fbufSave, this->fbuf);
+void PreRender_RestoreFramebuffer(PreRender* this, Gfx** gfxP) {
+    PreRender_CopyImage(this, gfxP, this->fbufSave, this->fbuf);
 }
 
 /**
  * Copies part of `this->fbufSave` in the region (this->ulx, this->uly), (this->lrx, this->lry) to the same location in
  * `this->fbuf`.
  */
-void PreRender_CopyImageRegion(PreRender* this, Gfx** gfxp) {
-    PreRender_CopyImageRegionImpl(this, gfxp);
+void PreRender_CopyImageRegion(PreRender* this, Gfx** gfxP) {
+    PreRender_CopyImageRegionImpl(this, gfxP);
 }
 
 /**
diff --git a/src/code/code_800ACE70.c b/src/code/code_800ACE70.c
deleted file mode 100644
index a7252904d..000000000
--- a/src/code/code_800ACE70.c
+++ /dev/null
@@ -1,97 +0,0 @@
-#include "global.h"
-
-// Note : This file is related to z_vismono, the original name was probably z_vis<something before "mono"
-// alphabetically>
-
-Gfx D_8012AC00[] = {
-    gsDPSetOtherMode(G_AD_PATTERN | G_CD_MAGICSQ | G_CK_NONE | G_TC_CONV | G_TF_POINT | G_TT_NONE | G_TL_TILE |
-                         G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
-                     G_AC_NONE | G_ZS_PRIM | G_RM_VISCVG | G_RM_VISCVG2),
-    gsDPFillRectangle(0, 0, SCREEN_WIDTH - 1, SCREEN_HEIGHT - 1),
-    gsDPPipeSync(),
-    gsDPSetBlendColor(0, 0, 0, 8),
-    gsSPEndDisplayList(),
-};
-
-Gfx D_8012AC28[] = {
-    gsDPSetOtherMode(G_AD_PATTERN | G_CD_MAGICSQ | G_CK_NONE | G_TC_CONV | G_TF_POINT | G_TT_NONE | G_TL_TILE |
-                         G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
-                     G_AC_NONE | G_ZS_PRIM | IM_RD | CVG_DST_CLAMP | ZMODE_OPA | FORCE_BL |
-                         GBL_c1(G_BL_CLR_FOG, G_BL_A_FOG, G_BL_CLR_MEM, G_BL_A_MEM) |
-                         GBL_c2(G_BL_CLR_FOG, G_BL_A_FOG, G_BL_CLR_MEM, G_BL_A_MEM)),
-    gsDPFillRectangle(0, 0, SCREEN_WIDTH - 1, SCREEN_HEIGHT - 1),
-    gsSPEndDisplayList(),
-};
-
-Gfx D_8012AC40[] = {
-    gsDPSetOtherMode(G_AD_PATTERN | G_CD_MAGICSQ | G_CK_NONE | G_TC_CONV | G_TF_POINT | G_TT_NONE | G_TL_TILE |
-                         G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
-                     G_AC_NONE | G_ZS_PRIM | IM_RD | CVG_DST_CLAMP | ZMODE_OPA | FORCE_BL |
-                         GBL_c1(G_BL_CLR_IN, G_BL_0, G_BL_CLR_MEM, G_BL_A_MEM) |
-                         GBL_c2(G_BL_CLR_IN, G_BL_0, G_BL_CLR_MEM, G_BL_A_MEM)),
-
-    gsDPFillRectangle(0, 0, SCREEN_WIDTH - 1, SCREEN_HEIGHT - 1),
-    gsSPEndDisplayList(),
-};
-
-Gfx D_8012AC58[] = {
-    gsDPSetCombineMode(G_CC_PRIMITIVE, G_CC_PRIMITIVE),
-    gsDPSetOtherMode(G_AD_NOTPATTERN | G_CD_DISABLE | G_CK_NONE | G_TC_CONV | G_TF_POINT | G_TT_NONE | G_TL_TILE |
-                         G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
-                     G_AC_NONE | G_ZS_PRIM | G_RM_CLD_SURF | G_RM_CLD_SURF2),
-    gsDPFillRectangle(0, 0, SCREEN_WIDTH - 1, SCREEN_HEIGHT - 1),
-    gsDPSetOtherMode(G_AD_PATTERN | G_CD_MAGICSQ | G_CK_NONE | G_TC_CONV | G_TF_POINT | G_TT_NONE | G_TL_TILE |
-                         G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
-                     G_AC_NONE | G_ZS_PRIM | IM_RD | CVG_DST_CLAMP | ZMODE_OPA | FORCE_BL |
-                         GBL_c1(G_BL_CLR_IN, G_BL_0, G_BL_CLR_MEM, G_BL_A_MEM) |
-                         GBL_c2(G_BL_CLR_IN, G_BL_0, G_BL_CLR_MEM, G_BL_A_MEM)),
-    gsDPFillRectangle(0, 0, SCREEN_WIDTH - 1, SCREEN_HEIGHT - 1),
-    gsSPEndDisplayList(),
-};
-
-// Init
-void func_800ACE70(struct_801664F0* this) {
-    this->type = 0;
-    this->setScissor = false;
-    this->color.r = 255;
-    this->color.g = 255;
-    this->color.b = 255;
-    this->color.a = 255;
-}
-
-// Destroy
-void func_800ACE90(struct_801664F0* this) {
-}
-
-// Draw
-void func_800ACE98(struct_801664F0* this, Gfx** gfxp) {
-    Gfx* gfx = *gfxp;
-
-    gDPPipeSync(gfx++);
-    gDPSetPrimDepth(gfx++, 0xFFFF, 0xFFFF);
-
-    if (this->setScissor == true) {
-        gDPSetScissor(gfx++, G_SC_NON_INTERLACE, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
-    }
-
-    switch (this->type) {
-        case 1:
-            gSPDisplayList(gfx++, D_8012AC40);
-            break;
-        case 2:
-            gDPSetColor(gfx++, G_SETPRIMCOLOR, this->color.rgba);
-            gSPDisplayList(gfx++, D_8012AC58);
-            break;
-        case 3:
-            gDPSetColor(gfx++, G_SETBLENDCOLOR, this->color.rgba);
-            gSPDisplayList(gfx++, D_8012AC00);
-            break;
-        case 4:
-            gDPSetColor(gfx++, G_SETFOGCOLOR, this->color.rgba);
-            gSPDisplayList(gfx++, D_8012AC28);
-            break;
-    }
-
-    gDPPipeSync(gfx++);
-    *gfxp = gfx;
-}
diff --git a/src/code/code_800AD920.c b/src/code/code_800AD920.c
deleted file mode 100644
index 94479e164..000000000
--- a/src/code/code_800AD920.c
+++ /dev/null
@@ -1,60 +0,0 @@
-#include "global.h"
-
-// Note : This file is related to z_vismono, the original name was probably z_vis<something after "mono" alphabetically>
-
-// z-buffer
-extern u16 D_0E000000[];
-
-// Init
-void func_800AD920(struct_80166500* this) {
-    this->useRgba = false;
-    this->setScissor = false;
-    this->primColor.r = 255;
-    this->primColor.g = 255;
-    this->primColor.b = 255;
-    this->primColor.a = 255;
-    this->envColor.a = 255;
-    this->envColor.r = 0;
-    this->envColor.g = 0;
-    this->envColor.b = 0;
-}
-
-// Destroy
-void func_800AD950(struct_80166500* this) {
-}
-
-// Draw
-void func_800AD958(struct_80166500* this, Gfx** gfxp) {
-    Gfx* gfx = *gfxp;
-    u16* tex = D_0E000000;
-    s32 fmt = !this->useRgba ? G_IM_FMT_IA : G_IM_FMT_RGBA;
-    s32 y;
-    s32 height = 6;
-
-    gDPPipeSync(gfx++);
-    if (this->setScissor == true) {
-        gDPSetScissor(gfx++, G_SC_NON_INTERLACE, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
-    }
-
-    gDPSetOtherMode(gfx++,
-                    G_AD_DISABLE | G_CD_MAGICSQ | G_CK_NONE | G_TC_FILT | G_TF_POINT | G_TT_NONE | G_TL_TILE |
-                        G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
-                    G_AC_NONE | G_ZS_PRIM | G_RM_OPA_SURF | G_RM_OPA_SURF2);
-    gDPSetCombineLERP(gfx++, PRIMITIVE, ENVIRONMENT, TEXEL0, ENVIRONMENT, PRIMITIVE, ENVIRONMENT, TEXEL0, ENVIRONMENT,
-                      PRIMITIVE, ENVIRONMENT, TEXEL0, ENVIRONMENT, PRIMITIVE, ENVIRONMENT, TEXEL0, ENVIRONMENT);
-
-    gDPSetColor(gfx++, G_SETPRIMCOLOR, this->primColor.rgba);
-    gDPSetColor(gfx++, G_SETENVCOLOR, this->envColor.rgba);
-
-    for (y = 0; y <= SCREEN_HEIGHT - height; y += height) {
-        gDPLoadTextureBlock(gfx++, tex, fmt, G_IM_SIZ_16b, SCREEN_WIDTH, height, 0, G_TX_NOMIRROR | G_TX_CLAMP,
-                            G_TX_NOMIRROR | G_TX_CLAMP, G_TX_NOMASK, G_TX_NOMASK, G_TX_NOLOD, G_TX_NOLOD);
-
-        gSPTextureRectangle(gfx++, 0, y << 2, SCREEN_WIDTH << 2, (y + height) << 2, G_TX_RENDERTILE, 0, 0, 1 << 10,
-                            1 << 10);
-        tex += SCREEN_WIDTH * height;
-    }
-
-    gDPPipeSync(gfx++);
-    *gfxp = gfx;
-}
diff --git a/src/code/game.c b/src/code/game.c
index 10fdcbefd..183a18b46 100644
--- a/src/code/game.c
+++ b/src/code/game.c
@@ -2,9 +2,9 @@
 #include "terminal.h"
 
 SpeedMeter D_801664D0;
-struct_801664F0 D_801664F0;
-struct_80166500 D_80166500;
-VisMono sMonoColors;
+VisCvg sVisCvg;
+VisZBuf sVisZBuf;
+VisMono sVisMono;
 ViMode sViMode;
 FaultClient sGameFaultClient;
 u16 sLastButtonPressed;
@@ -22,40 +22,43 @@ void GameState_FaultPrint(void) {
     }
 }
 
-void GameState_SetFBFilter(Gfx** gfx) {
-    Gfx* gfxP = *gfx;
-
-    if ((R_FB_FILTER_TYPE > 0) && (R_FB_FILTER_TYPE < 5)) {
-        D_801664F0.type = R_FB_FILTER_TYPE;
-        D_801664F0.color.r = R_FB_FILTER_PRIM_COLOR(0);
-        D_801664F0.color.g = R_FB_FILTER_PRIM_COLOR(1);
-        D_801664F0.color.b = R_FB_FILTER_PRIM_COLOR(2);
-        D_801664F0.color.a = R_FB_FILTER_A;
-        func_800ACE98(&D_801664F0, &gfxP);
-    } else if ((R_FB_FILTER_TYPE == 5) || (R_FB_FILTER_TYPE == 6)) {
-        D_80166500.useRgba = (R_FB_FILTER_TYPE == 6);
-        D_80166500.primColor.r = R_FB_FILTER_PRIM_COLOR(0);
-        D_80166500.primColor.g = R_FB_FILTER_PRIM_COLOR(1);
-        D_80166500.primColor.b = R_FB_FILTER_PRIM_COLOR(2);
-        D_80166500.primColor.a = R_FB_FILTER_A;
-        D_80166500.envColor.r = R_FB_FILTER_ENV_COLOR(0);
-        D_80166500.envColor.g = R_FB_FILTER_ENV_COLOR(1);
-        D_80166500.envColor.b = R_FB_FILTER_ENV_COLOR(2);
-        D_80166500.envColor.a = R_FB_FILTER_A;
-        func_800AD958(&D_80166500, &gfxP);
-    } else if (R_FB_FILTER_TYPE == 7) {
-        sMonoColors.unk_00 = 0;
-        sMonoColors.primColor.r = R_FB_FILTER_PRIM_COLOR(0);
-        sMonoColors.primColor.g = R_FB_FILTER_PRIM_COLOR(1);
-        sMonoColors.primColor.b = R_FB_FILTER_PRIM_COLOR(2);
-        sMonoColors.primColor.a = R_FB_FILTER_A;
-        sMonoColors.envColor.r = R_FB_FILTER_ENV_COLOR(0);
-        sMonoColors.envColor.g = R_FB_FILTER_ENV_COLOR(1);
-        sMonoColors.envColor.b = R_FB_FILTER_ENV_COLOR(2);
-        sMonoColors.envColor.a = R_FB_FILTER_A;
-        VisMono_Draw(&sMonoColors, &gfxP);
+void GameState_SetFBFilter(Gfx** gfxP) {
+    Gfx* gfx = *gfxP;
+
+    if ((R_FB_FILTER_TYPE >= FB_FILTER_CVG_RGB) && (R_FB_FILTER_TYPE <= FB_FILTER_CVG_RGB_FOG)) {
+        // Visualize coverage
+        sVisCvg.vis.type = FB_FILTER_TO_CVG_TYPE(R_FB_FILTER_TYPE);
+        sVisCvg.vis.primColor.r = R_FB_FILTER_PRIM_COLOR(0);
+        sVisCvg.vis.primColor.g = R_FB_FILTER_PRIM_COLOR(1);
+        sVisCvg.vis.primColor.b = R_FB_FILTER_PRIM_COLOR(2);
+        sVisCvg.vis.primColor.a = R_FB_FILTER_A;
+        VisCvg_Draw(&sVisCvg, &gfx);
+    } else if ((R_FB_FILTER_TYPE == FB_FILTER_ZBUF_IA) || (R_FB_FILTER_TYPE == FB_FILTER_ZBUF_RGBA)) {
+        // Visualize z-buffer
+        sVisZBuf.vis.type = (R_FB_FILTER_TYPE == FB_FILTER_ZBUF_RGBA);
+        sVisZBuf.vis.primColor.r = R_FB_FILTER_PRIM_COLOR(0);
+        sVisZBuf.vis.primColor.g = R_FB_FILTER_PRIM_COLOR(1);
+        sVisZBuf.vis.primColor.b = R_FB_FILTER_PRIM_COLOR(2);
+        sVisZBuf.vis.primColor.a = R_FB_FILTER_A;
+        sVisZBuf.vis.envColor.r = R_FB_FILTER_ENV_COLOR(0);
+        sVisZBuf.vis.envColor.g = R_FB_FILTER_ENV_COLOR(1);
+        sVisZBuf.vis.envColor.b = R_FB_FILTER_ENV_COLOR(2);
+        sVisZBuf.vis.envColor.a = R_FB_FILTER_A;
+        VisZBuf_Draw(&sVisZBuf, &gfx);
+    } else if (R_FB_FILTER_TYPE == FB_FILTER_MONO) {
+        // Monochrome filter
+        sVisMono.vis.type = 0;
+        sVisMono.vis.primColor.r = R_FB_FILTER_PRIM_COLOR(0);
+        sVisMono.vis.primColor.g = R_FB_FILTER_PRIM_COLOR(1);
+        sVisMono.vis.primColor.b = R_FB_FILTER_PRIM_COLOR(2);
+        sVisMono.vis.primColor.a = R_FB_FILTER_A;
+        sVisMono.vis.envColor.r = R_FB_FILTER_ENV_COLOR(0);
+        sVisMono.vis.envColor.g = R_FB_FILTER_ENV_COLOR(1);
+        sVisMono.vis.envColor.b = R_FB_FILTER_ENV_COLOR(2);
+        sVisMono.vis.envColor.a = R_FB_FILTER_A;
+        VisMono_Draw(&sVisMono, &gfx);
     }
-    *gfx = gfxP;
+    *gfxP = gfx;
 }
 
 void func_800C4344(GameState* gameState) {
@@ -110,7 +113,7 @@ void func_800C4344(GameState* gameState) {
     }
 }
 
-void GameState_DrawInputDisplay(u16 input, Gfx** gfx) {
+void GameState_DrawInputDisplay(u16 input, Gfx** gfxP) {
     static const u16 sInpDispBtnColors[] = {
         GPACK_RGBA5551(255, 255, 0, 1),   GPACK_RGBA5551(255, 255, 0, 1),   GPACK_RGBA5551(255, 255, 0, 1),
         GPACK_RGBA5551(255, 255, 0, 1),   GPACK_RGBA5551(120, 120, 120, 1), GPACK_RGBA5551(120, 120, 120, 1),
@@ -120,10 +123,10 @@ void GameState_DrawInputDisplay(u16 input, Gfx** gfx) {
         GPACK_RGBA5551(0, 0, 255, 1),
     };
     s32 i, j, k;
-    Gfx* gfxP = *gfx;
+    Gfx* gfx = *gfxP;
 
-    gDPPipeSync(gfxP++);
-    gDPSetOtherMode(gfxP++,
+    gDPPipeSync(gfx++);
+    gDPSetOtherMode(gfx++,
                     G_AD_PATTERN | G_CD_MAGICSQ | G_CK_NONE | G_TC_CONV | G_TF_POINT | G_TT_NONE | G_TL_TILE |
                         G_TD_CLAMP | G_TP_NONE | G_CYC_FILL | G_PM_NPRIMITIVE,
                     G_AC_NONE | G_ZS_PIXEL | G_RM_NOOP | G_RM_NOOP2);
@@ -131,14 +134,14 @@ void GameState_DrawInputDisplay(u16 input, Gfx** gfx) {
     for (i = 0; i < 16; i++) {
         j = i;
         if (input & (1 << i)) {
-            gDPSetFillColor(gfxP++, (sInpDispBtnColors[i] << 0x10) | sInpDispBtnColors[i]);
+            gDPSetFillColor(gfx++, (sInpDispBtnColors[i] << 0x10) | sInpDispBtnColors[i]);
             k = i + 1;
-            gDPFillRectangle(gfxP++, (j * 4) + 226, 220, (k * 4) + 225, 223);
-            gDPPipeSync(gfxP++);
+            gDPFillRectangle(gfx++, (j * 4) + 226, 220, (k * 4) + 225, 223);
+            gDPPipeSync(gfx++);
         }
     }
 
-    *gfx = gfxP;
+    *gfxP = gfx;
 }
 
 void GameState_Draw(GameState* gameState, GraphicsContext* gfxCtx) {
@@ -413,9 +416,9 @@ void GameState_Init(GameState* gameState, GameStateFunc init, GraphicsContext* g
 
     startTime = endTime;
     LogUtils_CheckNullPointer("this->cleanup", gameState->destroy, "../game.c", 1088);
-    func_800ACE70(&D_801664F0);
-    func_800AD920(&D_80166500);
-    VisMono_Init(&sMonoColors);
+    VisCvg_Init(&sVisCvg);
+    VisZBuf_Init(&sVisZBuf);
+    VisMono_Init(&sVisMono);
     if (R_VI_MODE_EDIT_STATE == VI_MODE_EDIT_STATE_INACTIVE) {
         ViMode_Init(&sViMode);
     }
@@ -443,9 +446,9 @@ void GameState_Destroy(GameState* gameState) {
     }
     Rumble_Destroy();
     SpeedMeter_Destroy(&D_801664D0);
-    func_800ACE90(&D_801664F0);
-    func_800AD950(&D_80166500);
-    VisMono_Destroy(&sMonoColors);
+    VisCvg_Destroy(&sVisCvg);
+    VisZBuf_Destroy(&sVisZBuf);
+    VisMono_Destroy(&sVisMono);
     if (R_VI_MODE_EDIT_STATE == VI_MODE_EDIT_STATE_INACTIVE) {
         ViMode_Destroy(&sViMode);
     }
diff --git a/src/code/graph.c b/src/code/graph.c
index 3d53f891c..fd79efac5 100644
--- a/src/code/graph.c
+++ b/src/code/graph.c
@@ -513,17 +513,17 @@ Gfx* Graph_BranchDlist(Gfx* gfx, Gfx* dst) {
     return dst;
 }
 
-void* Graph_DlistAlloc(Gfx** gfx, u32 size) {
+void* Graph_DlistAlloc(Gfx** gfxP, u32 size) {
     u8* ptr;
     Gfx* dst;
 
     size = ALIGN8(size);
 
-    ptr = (u8*)(*gfx + 1);
+    ptr = (u8*)(*gfxP + 1);
 
     dst = (Gfx*)(ptr + size);
-    gSPBranchList(*gfx, dst);
+    gSPBranchList(*gfxP, dst);
 
-    *gfx = dst;
+    *gfxP = dst;
     return ptr;
 }
diff --git a/src/code/z_play.c b/src/code/z_play.c
index c1840037e..c4d891548 100644
--- a/src/code/z_play.c
+++ b/src/code/z_play.c
@@ -8,7 +8,7 @@ Input* D_8012D1F8 = NULL;
 
 TransitionTile sTransitionTile;
 s32 gTransitionTileState;
-VisMono D_80161498;
+VisMono sPlayVisMono;
 Color_RGBA8_u32 gVisMonoColor;
 FaultClient D_801614B8;
 s16 sTransitionFillTimer;
@@ -199,7 +199,7 @@ void Play_Destroy(GameState* thisx) {
 
     Letterbox_Destroy();
     TransitionFade_Destroy(&this->transitionFadeFlash);
-    VisMono_Destroy(&D_80161498);
+    VisMono_Destroy(&sPlayVisMono);
 
     if (gSaveContext.save.linkAge != this->linkAgeOnLoad) {
         Inventory_SwapAgeEquipment();
@@ -390,7 +390,7 @@ void Play_Init(GameState* thisx) {
     TransitionFade_SetType(&this->transitionFadeFlash, TRANS_INSTANCE_TYPE_FADE_FLASH);
     TransitionFade_SetColor(&this->transitionFadeFlash, RGBA8(160, 160, 160, 255));
     TransitionFade_Start(&this->transitionFadeFlash);
-    VisMono_Init(&D_80161498);
+    VisMono_Init(&sPlayVisMono);
     gVisMonoColor.a = 0;
     CutsceneFlags_UnsetAll(this);
 
@@ -1103,8 +1103,8 @@ void Play_Draw(PlayState* this) {
             TransitionFade_Draw(&this->transitionFadeFlash, &gfxP);
 
             if (gVisMonoColor.a > 0) {
-                D_80161498.primColor.rgba = gVisMonoColor.rgba;
-                VisMono_Draw(&D_80161498, &gfxP);
+                sPlayVisMono.vis.primColor.rgba = gVisMonoColor.rgba;
+                VisMono_Draw(&sPlayVisMono, &gfxP);
             }
 
             gSPEndDisplayList(gfxP++);
diff --git a/src/code/z_rcp.c b/src/code/z_rcp.c
index aa4d56998..3b9a85098 100644
--- a/src/code/z_rcp.c
+++ b/src/code/z_rcp.c
@@ -907,8 +907,8 @@ Gfx* Gfx_SetupDL(Gfx* gfx, u32 i) {
     return Gfx_SetupDLImpl(gfx, i);
 }
 
-void Gfx_SetupDLAtPtr(Gfx** gfxp, u32 i) {
-    *gfxp = Gfx_SetupDL(*gfxp, i);
+void Gfx_SetupDLAtPtr(Gfx** gfxP, u32 i) {
+    *gfxP = Gfx_SetupDL(*gfxP, i);
 }
 
 Gfx* Gfx_SetupDL_57(Gfx* gfx) {
@@ -1193,11 +1193,11 @@ void Gfx_SetupDL_39Overlay(GraphicsContext* gfxCtx) {
     CLOSE_DISPS(gfxCtx, "../z_rcp.c", 1811);
 }
 
-void Gfx_SetupDL_39Ptr(Gfx** gfxp) {
-    Gfx* gfx = *gfxp;
+void Gfx_SetupDL_39Ptr(Gfx** gfxP) {
+    Gfx* gfx = *gfxP;
 
     gSPDisplayList(gfx++, sSetupDL[SETUPDL_39]);
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
 void Gfx_SetupDL_40Opa(GraphicsContext* gfxCtx) {
@@ -1345,12 +1345,12 @@ void Gfx_SetupDL_56Opa(GraphicsContext* gfxCtx) {
     CLOSE_DISPS(gfxCtx, "../z_rcp.c", 2090);
 }
 
-void Gfx_SetupDL_56Ptr(Gfx** gfxp) {
-    Gfx* gfx = *gfxp;
+void Gfx_SetupDL_56Ptr(Gfx** gfxP) {
+    Gfx* gfx = *gfxP;
 
     gSPDisplayList(gfx++, sSetupDL[SETUPDL_56]);
 
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
 void Gfx_SetupDL_59Opa(GraphicsContext* gfxCtx) {
@@ -1361,8 +1361,8 @@ void Gfx_SetupDL_59Opa(GraphicsContext* gfxCtx) {
     CLOSE_DISPS(gfxCtx, "../z_rcp.c", 2116);
 }
 
-Gfx* Gfx_BranchTexScroll(Gfx** gfxp, u32 x, u32 y, s32 width, s32 height) {
-    Gfx* displayList = Graph_DlistAlloc(gfxp, 3 * sizeof(Gfx));
+Gfx* Gfx_BranchTexScroll(Gfx** gfxP, u32 x, u32 y, s32 width, s32 height) {
+    Gfx* displayList = Graph_DlistAlloc(gfxP, 3 * sizeof(Gfx));
 
     gDPTileSync(displayList);
     gDPSetTileSize(displayList + 1, G_TX_RENDERTILE, x, y, x + ((width - 1) << 2), y + ((height - 1) << 2));
@@ -1371,8 +1371,8 @@ Gfx* Gfx_BranchTexScroll(Gfx** gfxp, u32 x, u32 y, s32 width, s32 height) {
     return displayList;
 }
 
-Gfx* func_80094E54(Gfx** gfxp, u32 x, u32 y) {
-    return Gfx_BranchTexScroll(gfxp, x, y, 0, 0);
+Gfx* func_80094E54(Gfx** gfxP, u32 x, u32 y) {
+    return Gfx_BranchTexScroll(gfxP, x, y, 0, 0);
 }
 
 Gfx* func_80094E78(GraphicsContext* gfxCtx, u32 x, u32 y) {
diff --git a/src/code/z_view.c b/src/code/z_view.c
index 328441150..117957d1b 100644
--- a/src/code/z_view.c
+++ b/src/code/z_view.c
@@ -539,8 +539,8 @@ s32 View_UpdateViewingMatrix(View* view) {
     return 1;
 }
 
-s32 View_ApplyTo(View* view, s32 mask, Gfx** gfxp) {
-    Gfx* gfx = *gfxp;
+s32 View_ApplyTo(View* view, s32 mask, Gfx** gfxP) {
+    Gfx* gfx = *gfxP;
     GraphicsContext* gfxCtx = view->gfxCtx;
     s32 width;
     s32 height;
@@ -606,7 +606,7 @@ s32 View_ApplyTo(View* view, s32 mask, Gfx** gfxp) {
     }
 
     view->flags = 0;
-    *gfxp = gfx;
+    *gfxP = gfx;
 
     return 1;
 }
diff --git a/src/code/z_viscvg.c b/src/code/z_viscvg.c
new file mode 100644
index 000000000..9caf39a3f
--- /dev/null
+++ b/src/code/z_viscvg.c
@@ -0,0 +1,145 @@
+/**
+ * @file z_viscvg.c
+ *
+ * This file implements full-screen frame buffer effects involving the visualization of Coverage in various ways.
+ *
+ * Coverage is roughly how much of a pixel is covered by a primitive; the final coverage for a frame is stored in the
+ * color image alpha component where it is used for antialiasing, see PreRender.c and §15 of the programming manual for
+ * details.
+ *
+ * To understand this file, it is helpful to remember that A_MEM is essentially synonymous with coverage, and that
+ * `GBL_c1/2(p, a, m, b)` usually represents the RDP blender calculation `(p * a + m * b)`.
+ * Note the division step that is often included in the blender calculation is omitted; the division is skipped if
+ * force blending (FORCE_BL) is set, which is the case for all render modes used in this file.
+ *
+ * Coverage is full when not on an edge, while on an edge it is usually lower. Since coverage is treated as an alpha
+ * value, edges of primitives where coverage is lower will show up darker than primitive interiors in all of the
+ * available modes.
+ *
+ * Coverage is abbreviated to "cvg"; "FB RGB" ("framebuffer red/green/blue") is the color the pixel originally had
+ * before the filter is applied.
+ */
+
+#include "global.h"
+
+/**
+ * Draws only coverage: does not retain any of the original pixel RGB, primColor is used as background color.
+ */
+Gfx sCoverageOnlyDL[] = {
+    gsDPSetOtherMode(G_AD_PATTERN | G_CD_MAGICSQ | G_CK_NONE | G_TC_CONV | G_TF_POINT | G_TT_NONE | G_TL_TILE |
+                         G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
+                     G_AC_NONE | G_ZS_PRIM | G_RM_VISCVG | G_RM_VISCVG2),
+    // (blendColor RGB) * (cvg)
+    gsDPFillRectangle(0, 0, SCREEN_WIDTH - 1, SCREEN_HEIGHT - 1),
+    gsDPPipeSync(),
+    gsDPSetBlendColor(0, 0, 0, 8),
+    gsSPEndDisplayList(),
+};
+
+/**
+ * Draws fog + coverage * RGB of pixels
+ *
+ * @bug This easily overflows the blender because the fog value is added to the coverage value.
+ */
+Gfx sCoverageRGBFogDL[] = {
+    gsDPSetOtherMode(G_AD_PATTERN | G_CD_MAGICSQ | G_CK_NONE | G_TC_CONV | G_TF_POINT | G_TT_NONE | G_TL_TILE |
+                         G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
+                     G_AC_NONE | G_ZS_PRIM | IM_RD | CVG_DST_CLAMP | ZMODE_OPA | FORCE_BL |
+                         GBL_c1(G_BL_CLR_FOG, G_BL_A_FOG, G_BL_CLR_MEM, G_BL_A_MEM) |
+                         GBL_c2(G_BL_CLR_FOG, G_BL_A_FOG, G_BL_CLR_MEM, G_BL_A_MEM)),
+    // (fog RGB) * (fog alpha) + (FB RGB) * (cvg)
+    gsDPFillRectangle(0, 0, SCREEN_WIDTH - 1, SCREEN_HEIGHT - 1),
+    gsSPEndDisplayList(),
+};
+
+/**
+ * Draws coverage and RGB of pixels
+ */
+Gfx sCoverageRGBDL[] = {
+    gsDPSetOtherMode(G_AD_PATTERN | G_CD_MAGICSQ | G_CK_NONE | G_TC_CONV | G_TF_POINT | G_TT_NONE | G_TL_TILE |
+                         G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
+                     G_AC_NONE | G_ZS_PRIM | IM_RD | CVG_DST_CLAMP | ZMODE_OPA | FORCE_BL |
+                         GBL_c1(G_BL_CLR_IN, G_BL_0, G_BL_CLR_MEM, G_BL_A_MEM) |
+                         GBL_c2(G_BL_CLR_IN, G_BL_0, G_BL_CLR_MEM, G_BL_A_MEM)),
+    // (FB RGB) * (cvg)
+    gsDPFillRectangle(0, 0, SCREEN_WIDTH - 1, SCREEN_HEIGHT - 1),
+    gsSPEndDisplayList(),
+};
+
+/**
+ * Two stage filtering:
+ *
+ * 1. Apply a uniform color filter by transparently blending primColor with original frame. The "cloud surface"
+ * RenderMode is used to preserve the coverage for the second stage.
+ * 2. Second half is the same as `sCoverageRGBDL`'s, i.e. (RGB from stage 1) * cvg
+ */
+Gfx sCoverageRGBUniformDL[] = {
+    gsDPSetCombineMode(G_CC_PRIMITIVE, G_CC_PRIMITIVE),
+    gsDPSetOtherMode(G_AD_NOTPATTERN | G_CD_DISABLE | G_CK_NONE | G_TC_CONV | G_TF_POINT | G_TT_NONE | G_TL_TILE |
+                         G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
+                     G_AC_NONE | G_ZS_PRIM | G_RM_CLD_SURF | G_RM_CLD_SURF2),
+    // stage 1 color = (primColor RGB) * (primColor Alpha) + (FB RGB) * (1 - primColor Alpha)
+    gsDPFillRectangle(0, 0, SCREEN_WIDTH - 1, SCREEN_HEIGHT - 1),
+
+    gsDPSetOtherMode(G_AD_PATTERN | G_CD_MAGICSQ | G_CK_NONE | G_TC_CONV | G_TF_POINT | G_TT_NONE | G_TL_TILE |
+                         G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
+                     G_AC_NONE | G_ZS_PRIM | IM_RD | CVG_DST_CLAMP | ZMODE_OPA | FORCE_BL |
+                         GBL_c1(G_BL_CLR_IN, G_BL_0, G_BL_CLR_MEM, G_BL_A_MEM) |
+                         GBL_c2(G_BL_CLR_IN, G_BL_0, G_BL_CLR_MEM, G_BL_A_MEM)),
+    // final color = (stage 1 RGB) * (cvg)
+    gsDPFillRectangle(0, 0, SCREEN_WIDTH - 1, SCREEN_HEIGHT - 1),
+    gsSPEndDisplayList(),
+};
+
+void VisCvg_Init(VisCvg* this) {
+    this->vis.type = FB_FILTER_NONE;
+    this->vis.scissorType = VIS_NO_SETSCISSOR;
+    this->vis.primColor.r = 255;
+    this->vis.primColor.g = 255;
+    this->vis.primColor.b = 255;
+    this->vis.primColor.a = 255;
+}
+
+void VisCvg_Destroy(VisCvg* this) {
+}
+
+void VisCvg_Draw(VisCvg* this, Gfx** gfxP) {
+    Gfx* gfx = *gfxP;
+
+    gDPPipeSync(gfx++);
+    gDPSetPrimDepth(gfx++, 0xFFFF, 0xFFFF);
+
+    if (this->vis.scissorType == VIS_SETSCISSOR) {
+        gDPSetScissor(gfx++, G_SC_NON_INTERLACE, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
+    }
+
+    switch (this->vis.type) {
+        case FB_FILTER_CVG_RGB:
+            gSPDisplayList(gfx++, sCoverageRGBDL);
+            break;
+
+        case FB_FILTER_CVG_RGB_UNIFORM:
+            // Set primitive color for uniform color filter in custom RenderMode
+            gDPSetColor(gfx++, G_SETPRIMCOLOR, this->vis.primColor.rgba);
+            gSPDisplayList(gfx++, sCoverageRGBUniformDL);
+            break;
+
+        case FB_FILTER_CVG_ONLY:
+            // Set background color for G_RM_VISCVG
+            gDPSetColor(gfx++, G_SETBLENDCOLOR, this->vis.primColor.rgba);
+            gSPDisplayList(gfx++, sCoverageOnlyDL);
+            break;
+
+        case FB_FILTER_CVG_RGB_FOG:
+            // Set fog color for custom RenderMode, needs to be close to 0 to not overflow
+            gDPSetColor(gfx++, G_SETFOGCOLOR, this->vis.primColor.rgba);
+            gSPDisplayList(gfx++, sCoverageRGBFogDL);
+            break;
+
+        default:
+            break;
+    }
+
+    gDPPipeSync(gfx++);
+    *gfxP = gfx;
+}
diff --git a/src/code/z_vismono.c b/src/code/z_vismono.c
index de065988e..8f0a5653f 100644
--- a/src/code/z_vismono.c
+++ b/src/code/z_vismono.c
@@ -1,13 +1,19 @@
 /**
- * Color frame buffer effect to desaturate the colors.
+ * @file z_vismono.c
+ *
+ * This file implements a full-screen framebuffer effect for desaturating the contents of the framebuffer image.
+ *
+ * Broadly, this effect is achieved by reinterpreting the contents of the RGBA16 color image as indices into an IA16
+ * color palette that converts each color into the desaturated equivalent. More precise details can be found in inline
+ * comments.
  */
 
 #include "global.h"
 
 // Height of the fragments the color frame buffer (CFB) is split into.
 // It is the maximum amount of lines such that all rgba16 SCREEN_WIDTH-long lines fit into
-// the half of tmem (0x800 bytes) dedicated to color-indexed data.
-#define VISMONO_CFBFRAG_HEIGHT (0x800 / (SCREEN_WIDTH * G_IM_SIZ_16b_BYTES))
+// the half of TMEM dedicated to color-indexed data.
+#define VISMONO_CFBFRAG_HEIGHT ((TMEM_SIZE / 2) / (SCREEN_WIDTH * G_IM_SIZ_16b_BYTES))
 
 // Maximum size of the dlist written by `VisMono_DesaturateDList`.
 // `VisMono_DesaturateDList` consistently uses `VISMONO_DLSIZE - 2` double words, so this can be 2 less.
@@ -26,16 +32,16 @@ extern u16 D_0F000000[];
 
 void VisMono_Init(VisMono* this) {
     bzero(this, sizeof(VisMono));
-    this->unk_00 = 0;
-    this->setScissor = false;
-    this->primColor.r = 255;
-    this->primColor.g = 255;
-    this->primColor.b = 255;
-    this->primColor.a = 255;
-    this->envColor.r = 0;
-    this->envColor.g = 0;
-    this->envColor.b = 0;
-    this->envColor.a = 0;
+    this->vis.type = 0;
+    this->vis.scissorType = VIS_NO_SETSCISSOR;
+    this->vis.primColor.r = 255;
+    this->vis.primColor.g = 255;
+    this->vis.primColor.b = 255;
+    this->vis.primColor.a = 255;
+    this->vis.envColor.r = 0;
+    this->vis.envColor.g = 0;
+    this->vis.envColor.b = 0;
+    this->vis.envColor.a = 0;
 }
 
 void VisMono_Destroy(VisMono* this) {
@@ -95,6 +101,8 @@ Gfx* VisMono_DesaturateDList(VisMono* this, Gfx* gfx) {
 
         // Set texel 1 to be a CI8 image with width `SCREEN_WIDTH * 2` and height `VISMONO_CFBFRAG_HEIGHT`
         // Its position in texture image space is shifted along +S by 1
+        // Note the palette index for this tile has also been incremented from 0 to 1, however the palette index is
+        // ignored for CI8 texture sampling.
         gDPSetTile(gfx++, G_IM_FMT_CI, G_IM_SIZ_8b, SCREEN_WIDTH * 2 * G_IM_SIZ_8b_LINE_BYTES / 8, 0x0, 1, 1,
                    G_TX_NOMIRROR | G_TX_CLAMP, 0, 0, G_TX_NOMIRROR | G_TX_CLAMP, 0, 0);
         gDPSetTileSize(gfx++, 1, 1 << 2, 0, (SCREEN_WIDTH * 2) << 2, (VISMONO_CFBFRAG_HEIGHT - 1) << 2);
@@ -129,8 +137,8 @@ Gfx* VisMono_DesaturateDList(VisMono* this, Gfx* gfx) {
     return gfx;
 }
 
-void VisMono_Draw(VisMono* this, Gfx** gfxp) {
-    Gfx* gfx = *gfxp;
+void VisMono_Draw(VisMono* this, Gfx** gfxP) {
+    Gfx* gfx = *gfxP;
     u16* tlut;
     Gfx* dList;
     Gfx* dListEnd;
@@ -159,12 +167,12 @@ void VisMono_Draw(VisMono* this, Gfx** gfxp) {
 
     gDPPipeSync(gfx++);
 
-    if (this->setScissor == true) {
+    if (this->vis.scissorType == VIS_SETSCISSOR) {
         gDPSetScissor(gfx++, G_SC_NON_INTERLACE, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
     }
 
-    gDPSetColor(gfx++, G_SETPRIMCOLOR, this->primColor.rgba);
-    gDPSetColor(gfx++, G_SETENVCOLOR, this->envColor.rgba);
+    gDPSetColor(gfx++, G_SETPRIMCOLOR, this->vis.primColor.rgba);
+    gDPSetColor(gfx++, G_SETENVCOLOR, this->vis.envColor.rgba);
 
     gDPLoadTLUT_pal256(gfx++, tlut);
 
@@ -172,7 +180,7 @@ void VisMono_Draw(VisMono* this, Gfx** gfxp) {
 
     gDPPipeSync(gfx++);
 
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
 void VisMono_DrawOld(VisMono* this) {
diff --git a/src/code/z_viszbuf.c b/src/code/z_viszbuf.c
new file mode 100644
index 000000000..90080b79c
--- /dev/null
+++ b/src/code/z_viszbuf.c
@@ -0,0 +1,111 @@
+/**
+ * @file z_viszbuf.c
+ *
+ * This file implements a full-screen framebuffer effect for visualizing the z-buffer (AKA depth buffer), using either
+ * cycling RGBA or a single fading color.
+ *
+ * This is done by reading the z-buffer as if it were a color image, the format of which is specified by the selected
+ * vis type:
+ *  - VIS_ZBUF_TYPE_IA   : Produces a monotonic fade from primColor to envColor as depth increases.
+ *  - VIS_ZBUF_TYPE_RGBA : Produces vibrant almost-periodic-looking bands.
+ *
+ * In both cases this occurs because of the format the depth information takes: it is 18-bit, and is a nonnegative
+ * floating-point number with
+ *     bbb      mmmmmmmmmmm dd|dd
+ *     exponent mantissa    dz value (only first 16 bits visible to CPU, the least significant 2 bits of dz are ignored)
+ *
+ * Reading z-buffer as IA16:
+ *     bbbmmmmm mmmmmmdd
+ *     iiiiiiii aaaaaaaa
+ *
+ * Since floating-point numbers of this format have the same ordering as their binary/hex representation, increasing
+ * the depth also increases the intensity in the IA16 representation and hence the interpolation parameter used to
+ * combine primColor and envColor. The alpha is ignored by the RenderMode.
+ *
+ * Reading z-buffer as RGBA16:
+ *     bbbmm mmmmm mmmmd d
+ *     rrrrr ggggg bbbbb a
+ *
+ * The red increases monotonically with the depth. The significant visible oscillation is the green component, because
+ * it rolls over every time the second-most-significant bit of the mantissa increments. The blue component oscillates
+ * too rapidly to be particularly visible (it rolls over when the 7th-most-significant bit increments). The alpha is
+ * again ignored by the RenderMode.
+ */
+
+#include "global.h"
+
+// Height of the fragments the z-buffer is split into.
+// It is the maximum amount of lines such that all rgba16 SCREEN_WIDTH-long lines fit into TMEM.
+#define VISZBUF_ZBUFFRAG_HEIGHT (TMEM_SIZE / (SCREEN_WIDTH * G_IM_SIZ_16b_BYTES))
+
+// z-buffer
+extern u16 D_0E000000[];
+
+/**
+ * Initialise to IA type with white and black as default colors.
+ */
+void VisZBuf_Init(VisZBuf* this) {
+    this->vis.type = VIS_ZBUF_TYPE_IA;
+    this->vis.scissorType = VIS_NO_SETSCISSOR;
+    this->vis.primColor.r = 255;
+    this->vis.primColor.g = 255;
+    this->vis.primColor.b = 255;
+    this->vis.primColor.a = 255;
+    this->vis.envColor.a = 255;
+    this->vis.envColor.r = 0;
+    this->vis.envColor.g = 0;
+    this->vis.envColor.b = 0;
+}
+
+void VisZBuf_Destroy(VisZBuf* this) {
+}
+
+void VisZBuf_Draw(VisZBuf* this, Gfx** gfxP) {
+    Gfx* gfx = *gfxP;
+    u16* zbufFrag = D_0E000000;
+    s32 fmt;
+    s32 y;
+    s32 height;
+
+    if (this->vis.type == VIS_ZBUF_TYPE_IA) {
+        fmt = G_IM_FMT_IA;
+    } else { // VIS_ZBUF_TYPE_RGBA
+        fmt = G_IM_FMT_RGBA;
+    }
+
+    height = VISZBUF_ZBUFFRAG_HEIGHT;
+
+    gDPPipeSync(gfx++);
+    // Scissoring is only required if the scissor has not been set prior.
+    if (this->vis.scissorType == VIS_SETSCISSOR) {
+        gDPSetScissor(gfx++, G_SC_NON_INTERLACE, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
+    }
+
+    // No palette so can use all of TMEM.
+    // G_RM_OPA_SURF discards all information previously in the pixel, and the current alpha, leaving only the color
+    // from this filter.
+    gDPSetOtherMode(gfx++,
+                    G_AD_DISABLE | G_CD_MAGICSQ | G_CK_NONE | G_TC_FILT | G_TF_POINT | G_TT_NONE | G_TL_TILE |
+                        G_TD_CLAMP | G_TP_NONE | G_CYC_1CYCLE | G_PM_NPRIMITIVE,
+                    G_AC_NONE | G_ZS_PRIM | G_RM_OPA_SURF | G_RM_OPA_SURF2);
+
+    // LERP between primColor and envColor in 1-cycle mode using the z-buffer value.
+    gDPSetCombineLERP(gfx++, PRIMITIVE, ENVIRONMENT, TEXEL0, ENVIRONMENT, PRIMITIVE, ENVIRONMENT, TEXEL0, ENVIRONMENT,
+                      PRIMITIVE, ENVIRONMENT, TEXEL0, ENVIRONMENT, PRIMITIVE, ENVIRONMENT, TEXEL0, ENVIRONMENT);
+    gDPSetColor(gfx++, G_SETPRIMCOLOR, this->vis.primColor.rgba);
+    gDPSetColor(gfx++, G_SETENVCOLOR, this->vis.envColor.rgba);
+
+    for (y = 0; y <= SCREEN_HEIGHT - height; y += height) {
+        // Load a few lines of the z-buffer, as many as can fit in TMEM at once.
+        gDPLoadTextureBlock(gfx++, zbufFrag, fmt, G_IM_SIZ_16b, SCREEN_WIDTH, height, 0, G_TX_NOMIRROR | G_TX_CLAMP,
+                            G_TX_NOMIRROR | G_TX_CLAMP, G_TX_NOMASK, G_TX_NOMASK, G_TX_NOLOD, G_TX_NOLOD);
+
+        // Overwrite them with the calculated colors.
+        gSPTextureRectangle(gfx++, 0, y << 2, SCREEN_WIDTH << 2, (y + height) << 2, G_TX_RENDERTILE, 0, 0, 1 << 10,
+                            1 << 10);
+        zbufFrag += SCREEN_WIDTH * height;
+    }
+
+    gDPPipeSync(gfx++);
+    *gfxP = gfx;
+}
diff --git a/src/overlays/actors/ovl_En_Fz/z_en_fz.h b/src/overlays/actors/ovl_En_Fz/z_en_fz.h
index 5c54720f2..dafada3d2 100644
--- a/src/overlays/actors/ovl_En_Fz/z_en_fz.h
+++ b/src/overlays/actors/ovl_En_Fz/z_en_fz.h
@@ -16,7 +16,7 @@ typedef struct {
     /* 0x0010 */ Vec3f velocity;
     /* 0x001C */ Vec3f accel;
     /* 0x0028 */ char unk_28[0x4];
-    /* 0x002C */ s16 primAlpha; // transparency in RGBA colour system
+    /* 0x002C */ s16 primAlpha; // transparency in RGBA color system
     /* 0x002E */ s16 primAlphaState; // 0: increasing (more opaque) 1: decreasing (more transparent) 2: collision
     /* 0x0030 */ f32 xyScale;
     /* 0x0034 */ f32 xyScaleTarget;
@@ -42,7 +42,7 @@ typedef struct EnFz {
     /* 0x024C */ f32 iceSmokeFreezingSpawnHeight; // Height for Ice Smoke Spawn, only when freezing
     /* 0x0250 */ f32 unusedFloat; // Set to 135.0f
     /* 0x0254 */ f32 speedXZ; // Set to 4.0f when moving
-    /* 0x0258 */ u32 envAlpha; // transparency in RGBA colour system
+    /* 0x0258 */ u32 envAlpha; // transparency in RGBA color system
     /* 0x025C */ u16 unusedNum1; // Only set to 0
     /* 0x025E */ u16 unusedNum2; // Set to either 0 when hidden or 4000 when growing
     /* 0x0260 */ u8 state; // 0 (hidden) 1 (growning/shrinking) 2 (full size) 3 (melting from fire)
diff --git a/src/overlays/actors/ovl_En_Mag/z_en_mag.c b/src/overlays/actors/ovl_En_Mag/z_en_mag.c
index 60b1867d6..164252b17 100644
--- a/src/overlays/actors/ovl_En_Mag/z_en_mag.c
+++ b/src/overlays/actors/ovl_En_Mag/z_en_mag.c
@@ -262,9 +262,9 @@ void EnMag_Update(Actor* thisx, PlayState* play) {
     }
 }
 
-void EnMag_DrawTextureI8(Gfx** gfxp, void* texture, s16 texWidth, s16 texHeight, s16 rectLeft, s16 rectTop,
+void EnMag_DrawTextureI8(Gfx** gfxP, void* texture, s16 texWidth, s16 texHeight, s16 rectLeft, s16 rectTop,
                          s16 rectWidth, s16 rectHeight, u16 dsdx, u16 dtdy) {
-    Gfx* gfx = *gfxp;
+    Gfx* gfx = *gfxP;
 
     gDPLoadTextureBlock(gfx++, texture, G_IM_FMT_I, G_IM_SIZ_8b, texWidth, texHeight, 0, G_TX_NOMIRROR | G_TX_WRAP,
                         G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMASK, G_TX_NOMASK, G_TX_NOLOD, G_TX_NOLOD);
@@ -272,13 +272,13 @@ void EnMag_DrawTextureI8(Gfx** gfxp, void* texture, s16 texWidth, s16 texHeight,
     gSPTextureRectangle(gfx++, rectLeft << 2, rectTop << 2, (rectLeft + rectWidth) << 2, (rectTop + rectHeight) << 2,
                         G_TX_RENDERTILE, 0, 0, dsdx, dtdy);
 
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
-void EnMag_DrawEffectTextures(Gfx** gfxp, void* maskTex, void* effectTex, s16 maskWidth, s16 maskHeight,
+void EnMag_DrawEffectTextures(Gfx** gfxP, void* maskTex, void* effectTex, s16 maskWidth, s16 maskHeight,
                               s16 effectWidth, s16 effectHeight, s16 rectLeft, s16 rectTop, s16 rectWidth,
                               s16 rectHeight, u16 dsdx, u16 dtdy, u16 shifts, u16 shiftt, u16 flag, EnMag* this) {
-    Gfx* gfx = *gfxp;
+    Gfx* gfx = *gfxP;
 
     gDPLoadMultiBlock_4b(gfx++, maskTex, 0x0000, G_TX_RENDERTILE, G_IM_FMT_I, maskWidth, maskHeight, 0,
                          G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMASK, G_TX_NOMASK, G_TX_NOLOD,
@@ -294,11 +294,11 @@ void EnMag_DrawEffectTextures(Gfx** gfxp, void* maskTex, void* effectTex, s16 ma
     gSPTextureRectangle(gfx++, rectLeft << 2, rectTop << 2, (rectLeft + rectWidth) << 2, (rectTop + rectHeight) << 2,
                         G_TX_RENDERTILE, 0, 0, dsdx, dtdy);
 
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
-void EnMag_DrawImageRGBA32(Gfx** gfxp, s16 centerX, s16 centerY, u8* source, u32 width, u32 height) {
-    Gfx* gfx = *gfxp;
+void EnMag_DrawImageRGBA32(Gfx** gfxP, s16 centerX, s16 centerY, u8* source, u32 width, u32 height) {
+    Gfx* gfx = *gfxP;
     u8* curTexture;
     s32 textureCount;
     u32 rectLeft;
@@ -353,11 +353,11 @@ void EnMag_DrawImageRGBA32(Gfx** gfxp, s16 centerX, s16 centerY, u8* source, u32
         }
     }
 
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
-void EnMag_DrawCharTexture(Gfx** gfxp, u8* texture, s32 rectLeft, s32 rectTop) {
-    Gfx* gfx = *gfxp;
+void EnMag_DrawCharTexture(Gfx** gfxP, u8* texture, s32 rectLeft, s32 rectTop) {
+    Gfx* gfx = *gfxP;
 
     YREG(0) = 1024.0f / (YREG(1) / 100.0f);
     YREG(2) = 16.0f * (YREG(1) / 100.0f);
@@ -368,10 +368,10 @@ void EnMag_DrawCharTexture(Gfx** gfxp, u8* texture, s32 rectLeft, s32 rectTop) {
     gSPTextureRectangle(gfx++, rectLeft << 2, rectTop << 2, (rectLeft + YREG(2)) << 2, (rectTop + YREG(2)) << 2,
                         G_TX_RENDERTILE, 0, 0, YREG(0), YREG(0));
 
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
-void EnMag_DrawInner(Actor* thisx, PlayState* play, Gfx** gfxp) {
+void EnMag_DrawInner(Actor* thisx, PlayState* play, Gfx** gfxP) {
     static s16 textAlpha = 0;
     static s16 textFadeDirection = 0;
     static s16 textFadeTimer = 0;
@@ -389,7 +389,7 @@ void EnMag_DrawInner(Actor* thisx, PlayState* play, Gfx** gfxp) {
     EnMag* this = (EnMag*)thisx;
     Font* font = &this->font;
     s32 pad;
-    Gfx* gfx = *gfxp;
+    Gfx* gfx = *gfxP;
     u16 i, j, k;
     u16 rectLeft;
     u16 rectTop;
@@ -559,7 +559,7 @@ void EnMag_DrawInner(Actor* thisx, PlayState* play, Gfx** gfxp) {
         }
     }
 
-    *gfxp = gfx;
+    *gfxP = gfx;
 }
 
 void EnMag_Draw(Actor* thisx, PlayState* play) {
diff --git a/src/overlays/gamestates/ovl_title/z_title.c b/src/overlays/gamestates/ovl_title/z_title.c
index 30bb737d6..1849b253d 100644
--- a/src/overlays/gamestates/ovl_title/z_title.c
+++ b/src/overlays/gamestates/ovl_title/z_title.c
@@ -8,15 +8,15 @@
 #include "alloca.h"
 #include "assets/textures/nintendo_rogo_static/nintendo_rogo_static.h"
 
-void ConsoleLogo_PrintBuildInfo(Gfx** gfxp) {
-    Gfx* g;
+void ConsoleLogo_PrintBuildInfo(Gfx** gfxP) {
+    Gfx* gfx;
     GfxPrint* printer;
 
-    g = *gfxp;
-    g = Gfx_SetupDL_28(g);
+    gfx = *gfxP;
+    gfx = Gfx_SetupDL_28(gfx);
     printer = alloca(sizeof(GfxPrint));
     GfxPrint_Init(printer);
-    GfxPrint_Open(printer, g);
+    GfxPrint_Open(printer, gfx);
     GfxPrint_SetColor(printer, 255, 155, 255, 255);
     GfxPrint_SetPos(printer, 9, 21);
     GfxPrint_Printf(printer, "NOT MARIO CLUB VERSION");
@@ -25,9 +25,9 @@ void ConsoleLogo_PrintBuildInfo(Gfx** gfxp) {
     GfxPrint_Printf(printer, "[Creator:%s]", gBuildTeam);
     GfxPrint_SetPos(printer, 7, 24);
     GfxPrint_Printf(printer, "[Date:%s]", gBuildDate);
-    g = GfxPrint_Close(printer);
+    gfx = GfxPrint_Close(printer);
     GfxPrint_Destroy(printer);
-    *gfxp = g;
+    *gfxP = gfx;
 }
 
 // Note: In other rom versions this function also updates unk_1D4, coverAlpha, addAlpha, visibleDuration to calculate
diff --git a/src/overlays/misc/ovl_kaleido_scope/z_kaleido_debug.c b/src/overlays/misc/ovl_kaleido_scope/z_kaleido_debug.c
index 170b5860b..90c740027 100644
--- a/src/overlays/misc/ovl_kaleido_scope/z_kaleido_debug.c
+++ b/src/overlays/misc/ovl_kaleido_scope/z_kaleido_debug.c
@@ -34,12 +34,12 @@ static s16 sSlotItems[] = {
     ITEM_BOOMERANG,  ITEM_LENS_OF_TRUTH, ITEM_MAGIC_BEAN, ITEM_HAMMER,   ITEM_ARROW_LIGHT, ITEM_NAYRUS_LOVE,
 };
 
-void KaleidoScope_DrawDebugEditorText(Gfx** gfxp) {
+void KaleidoScope_DrawDebugEditorText(Gfx** gfxP) {
     GfxPrint printer;
     s32 pad[2];
 
     GfxPrint_Init(&printer);
-    GfxPrint_Open(&printer, *gfxp);
+    GfxPrint_Open(&printer, *gfxP);
 
     GfxPrint_SetPos(&printer, 4, 2);
     GfxPrint_SetColor(&printer, 255, 60, 0, 255);
@@ -75,7 +75,7 @@ void KaleidoScope_DrawDebugEditorText(Gfx** gfxp) {
     GfxPrint_SetPos(&printer, 28, 24);
     GfxPrint_Printf(&printer, "%s", "/4");
 
-    *gfxp = GfxPrint_Close(&printer);
+    *gfxP = GfxPrint_Close(&printer);
     GfxPrint_Destroy(&printer);
 }