Merge remote-tracking branch 'upstream' into tustin2121-patch-5

1 files changed, 1226 insertions, 0 deletions

diff --git a/src/image_processing_effects.c b/src/image_processing_effects.c
new file mode 100644
index 000000000..13794faf0
--- /dev/null
+++ b/src/image_processing_effects.c
@@ -0,0 +1,1226 @@
+#include "global.h"
+#include "image_processing_effects.h"
+#include "contest_painting.h"
+#include "constants/rgb.h"
+
+// IWRAM common
+u8 gCanvasColumnStart;
+u16 (*gCanvasPixels)[][32];
+u8 gCanvasRowEnd;
+u8 gCanvasHeight;
+u8 gCanvasColumnEnd;
+u8 gCanvasRowStart;
+u8 gCanvasMonPersonality;
+u8 gCanvasWidth;
+u16 *gCanvasPalette;
+u16 gCanvasPaletteStart;
+
+static void ApplyImageEffect_Pointillism(void);
+static void ApplyImageEffect_Blur(void);
+static void ApplyImageEffect_BlackOutline(void);
+static void ApplyImageEffect_Invert(void);
+static void ApplyImageEffect_BlackAndWhite(void);
+static void ApplyImageEffect_BlurRight(void);
+static void ApplyImageEffect_BlurDown(void);
+static void ApplyImageEffect_Shimmer(void);
+static void ApplyImageEffect_Grayscale(void);
+static void ApplyImageEffect_PersonalityColor(u8);
+static void ApplyImageEffect_RedChannelGrayscale(u8);
+static void ApplyImageEffect_RedChannelGrayscaleHighlight(u8);
+static void AddPointillismPoints(u16);
+static u16 ConvertColorToGrayscale(u16*);
+static u16 QuantizePixel_Blur(u16*, u16*, u16*);
+static u16 QuantizePixel_PersonalityColor(u16*, u8);
+static u16 QuantizePixel_BlackAndWhite(u16*);
+static u16 QuantizePixel_BlackOutline(u16*, u16*);
+static u16 QuantizePixel_Invert(u16*);
+static u16 QuantizePixel_BlurHard(u16*, u16*, u16*);
+static u16 QuantizePixel_MotionBlur(u16*, u16*);
+static u16 GetColorFromPersonality(u8);
+static void QuantizePalette_Standard(bool8);
+static void SetPresetPalette_PrimaryColors(void);
+static void QuantizePalette_PrimaryColors(void);
+static void SetPresetPalette_Grayscale(void);
+static void QuantizePalette_Grayscale(void);
+static void SetPresetPalette_GrayscaleSmall(void);
+static void QuantizePalette_GrayscaleSmall(void);
+static void SetPresetPalette_BlackAndWhite(void);
+static void QuantizePalette_BlackAndWhite(void);
+static u16 QuantizePixel_Standard(u16*);
+static u16 QuantizePixel_GrayscaleSmall(u16*);
+static u16 QuantizePixel_Grayscale(u16*);
+static u16 QuantizePixel_PrimaryColors(u16*);
+
+extern const u8 gPointillismPoints[][3];
+
+void ApplyImageProcessingEffects(struct ImageProcessingContext *context)
+{
+    gCanvasPixels = context->canvasPixels;
+    gCanvasMonPersonality = context->personality;
+    gCanvasColumnStart = context->columnStart;
+    gCanvasRowStart = context->rowStart;
+    gCanvasColumnEnd = context->columnEnd;
+    gCanvasRowEnd = context->rowEnd;
+    gCanvasWidth = context->canvasWidth;
+    gCanvasHeight = context->canvasHeight;
+
+    switch (context->effect)
+    {
+    case IMAGE_EFFECT_POINTILLISM:
+        ApplyImageEffect_Pointillism();
+        break;
+    case IMAGE_EFFECT_BLUR:
+        ApplyImageEffect_Blur();
+        break;
+    case IMAGE_EFFECT_OUTLINE_COLORED:
+        ApplyImageEffect_BlackOutline();
+        ApplyImageEffect_PersonalityColor(gCanvasMonPersonality);
+        break;
+    case IMAGE_EFFECT_INVERT_BLACK_WHITE:
+        ApplyImageEffect_BlackOutline();
+        ApplyImageEffect_Invert();
+        ApplyImageEffect_BlackAndWhite();
+    case IMAGE_EFFECT_INVERT:
+        ApplyImageEffect_Invert();
+        break;
+    case IMAGE_EFFECT_THICK_BLACK_WHITE:
+        ApplyImageEffect_BlackOutline();
+        ApplyImageEffect_BlurRight();
+        ApplyImageEffect_BlurRight();
+        ApplyImageEffect_BlurDown();
+        ApplyImageEffect_BlackAndWhite();
+        break;
+    case IMAGE_EFFECT_SHIMMER:
+        ApplyImageEffect_Shimmer();
+        break;
+    case IMAGE_EFFECT_OUTLINE:
+        ApplyImageEffect_BlackOutline();
+        break;
+    case IMAGE_EFFECT_BLUR_RIGHT:
+        ApplyImageEffect_BlurRight();
+        break;
+    case IMAGE_EFFECT_BLUR_DOWN:
+        ApplyImageEffect_BlurDown();
+        break;
+    case IMAGE_EFFECT_GRAYSCALE_LIGHT:
+        ApplyImageEffect_Grayscale();
+        ApplyImageEffect_RedChannelGrayscale(3);
+        break;
+    case IMAGE_EFFECT_CHARCOAL:
+        ApplyImageEffect_BlackOutline();
+        ApplyImageEffect_BlurRight();
+        ApplyImageEffect_BlurDown();
+        ApplyImageEffect_BlackAndWhite();
+        ApplyImageEffect_Blur();
+        ApplyImageEffect_Blur();
+        ApplyImageEffect_RedChannelGrayscale(2);
+        ApplyImageEffect_RedChannelGrayscaleHighlight(4);
+        break;
+    }
+}
+
+static void ApplyImageEffect_RedChannelGrayscale(u8 delta)
+{
+    u8 i, j;
+
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
+        {
+            if (!(0x8000 & *pixel))
+            {
+                // Gets the grayscale value, based on the pixel's red channel.
+                // Also adds a delta to skew lighter or darker.
+                u8 grayValue = (31 & *pixel);
+                grayValue += delta;
+                if (grayValue > 31)
+                    grayValue = 31;
+
+                *pixel = RGB2(grayValue, grayValue, grayValue);
+            }
+        }
+    }
+}
+
+static void ApplyImageEffect_RedChannelGrayscaleHighlight(u8 highlight)
+{
+    u8 i, j;
+
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
+        {
+            if (!(0x8000 & *pixel))
+            {
+                u8 grayValue = (31 & *pixel);
+                if (grayValue > 31 - highlight)
+                    grayValue = 31 - (highlight >> 1);
+
+                *pixel = RGB2(grayValue, grayValue, grayValue);
+            }
+        }
+    }
+}
+
+static void ApplyImageEffect_Pointillism(void)
+{
+    u32 i;
+    for (i = 0; i < 3200; i++)
+        AddPointillismPoints(i);
+}
+
+static void ApplyImageEffect_Grayscale(void)
+{
+    u8 i, j;
+
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
+        {
+            if (!(0x8000 & *pixel))
+                *pixel = ConvertColorToGrayscale(pixel);
+        }
+    }
+}
+
+static void ApplyImageEffect_Blur(void)
+{
+    u8 i, j;
+
+    for (i = 0; i < gCanvasColumnEnd; i++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][gCanvasRowStart * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart + i];
+        u16 prevPixel = *pixel;
+
+        j = 1;
+        pixel += gCanvasWidth;
+        while (j < gCanvasRowEnd - 1)
+        {
+            if (!(0x8000 & *pixel))
+            {
+                *pixel = QuantizePixel_Blur(&prevPixel, pixel, pixel + gCanvasWidth);
+                prevPixel = *pixel;
+            }
+
+            j++;
+            pixel += gCanvasWidth;
+        }
+    }
+}
+
+static void ApplyImageEffect_PersonalityColor(u8 personality)
+{
+    u8 i, j;
+
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
+        {
+            if (!(0x8000 & *pixel))
+                *pixel = QuantizePixel_PersonalityColor(pixel, personality);
+        }
+    }
+}
+
+static void ApplyImageEffect_BlackAndWhite(void)
+{
+    u8 i, j;
+
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
+        {
+            if (!(0x8000 & *pixel))
+                *pixel = QuantizePixel_BlackAndWhite(pixel);
+        }
+    }
+}
+
+static void ApplyImageEffect_BlackOutline(void)
+{
+    u8 i, j;
+    u16 *pixel;
+
+    // Handle top row of pixels first.
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        pixel = &pixelRow[gCanvasColumnStart];
+        *pixel = QuantizePixel_BlackOutline(pixel, pixel + 1);
+        for (i = 1, pixel++; i < gCanvasColumnEnd - 1; i++, pixel++)
+        {
+            *pixel = QuantizePixel_BlackOutline(pixel, pixel + 1);
+            *pixel = QuantizePixel_BlackOutline(pixel, pixel - 1);
+        }
+
+        *pixel = QuantizePixel_BlackOutline(pixel, pixel - 1);
+    }
+
+    // Handle each column from left to right.
+    for (i = 0; i < gCanvasColumnEnd; i++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][gCanvasRowStart * gCanvasWidth];
+        pixel = &pixelRow[gCanvasColumnStart + i];
+        *pixel = QuantizePixel_BlackOutline(pixel, pixel + gCanvasWidth);
+        for (j = 1, pixel += gCanvasWidth; j < gCanvasRowEnd - 1; j++, pixel += gCanvasWidth)
+        {
+            *pixel = QuantizePixel_BlackOutline(pixel, pixel + gCanvasWidth);
+            *pixel = QuantizePixel_BlackOutline(pixel, pixel - gCanvasWidth);
+        }
+
+        *pixel = QuantizePixel_BlackOutline(pixel, pixel - gCanvasWidth);
+    }
+}
+
+static void ApplyImageEffect_Invert(void)
+{
+    u8 i, j;
+
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
+        {
+            if (!(0x8000 & *pixel))
+                *pixel = QuantizePixel_Invert(pixel);
+        }
+    }
+}
+
+static void ApplyImageEffect_Shimmer(void)
+{
+    u8 i, j;
+    u16 *pixel;
+    u16 prevPixel;
+
+    // First, invert all of the colors.
+    pixel = (*gCanvasPixels)[0];
+    for (i = 0; i < 64; i++)
+    {
+        for (j = 0; j < 64; j++, pixel++)
+        {
+            if (!(0x8000 & *pixel))
+                *pixel = QuantizePixel_Invert(pixel);
+        }
+    }
+
+    // Blur the pixels twice.
+    for (j = 0; j < 64; j++)
+    {
+        pixel = &(*gCanvasPixels)[0][j];
+        prevPixel = *pixel;
+        *pixel = 0x8000;
+        for (i = 1, pixel += 64; i < 63; i++, pixel += 64)
+        {
+            if (!(0x8000 & *pixel))
+            {
+                *pixel = QuantizePixel_BlurHard(&prevPixel, pixel, pixel + 64);
+                prevPixel = *pixel;
+            }
+        }
+
+        *pixel = 0x8000;
+        pixel = &(*gCanvasPixels)[0][j];
+        prevPixel = *pixel;
+        *pixel = 0x8000;
+        for (i = 1, pixel += 64; i < 63; i++, pixel += 64)
+        {
+            if (!(0x8000 & *pixel))
+            {
+                *pixel = QuantizePixel_BlurHard(&prevPixel, pixel, pixel + 64);
+                prevPixel = *pixel;
+            }
+        }
+
+        *pixel = 0x8000;
+    }
+
+    // Finally, invert colors back to the original color space.
+    // The above blur causes the outline areas to darken, which makes
+    // this inversion give the effect of light outlines.
+    pixel = (*gCanvasPixels)[0];
+    for (i = 0; i < 64; i++)
+    {
+        for (j = 0; j < 64; j++, pixel++)
+        {
+            if (!(0x8000 & *pixel))
+                *pixel = QuantizePixel_Invert(pixel);
+        }
+    }
+}
+
+static void ApplyImageEffect_BlurRight(void)
+{
+    u8 i, j;
+
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        u16 prevPixel = *pixel;
+        for (i = 1, pixel++; i < gCanvasColumnEnd - 1; i++, pixel++)
+        {
+            if (!(0x8000 & *pixel))
+            {
+                *pixel = QuantizePixel_MotionBlur(&prevPixel, pixel);
+                prevPixel = *pixel;
+            }
+        }
+    }
+}
+
+static void ApplyImageEffect_BlurDown(void)
+{
+    u8 i, j;
+
+    for (i = 0; i < gCanvasColumnEnd; i++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][gCanvasRowStart * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart + i];
+        u16 prevPixel = *pixel;
+        for (j = 1, pixel += gCanvasWidth; j < gCanvasRowEnd - 1; j++, pixel += gCanvasWidth)
+        {
+            if (!(0x8000 & *pixel))
+            {
+                *pixel = QuantizePixel_MotionBlur(&prevPixel, pixel);
+                prevPixel = *pixel;
+            }
+        }
+    }
+}
+
+struct PointillismPoint
+{
+    u8 column;
+    u8 row;
+    u16 delta;
+};
+
+static void AddPointillismPoints(u16 arg0)
+{
+    u8 i;
+    bool8 offsetDownLeft;
+    u8 colorType;
+    struct PointillismPoint points[6];
+
+    points[0].column = gPointillismPoints[arg0][0];
+    points[0].row = gPointillismPoints[arg0][1];
+    points[0].delta = (gPointillismPoints[arg0][2] >> 3) & 7;
+
+    colorType = (gPointillismPoints[arg0][2] >> 1) & 3;
+    offsetDownLeft = gPointillismPoints[arg0][2] & 1;
+    for (i = 1; i < points[0].delta; i++)
+    {
+        if (!offsetDownLeft)
+        {
+            points[i].column = points[0].column - i;
+            points[i].row = points[0].row + i;
+        }
+        else
+        {
+            points[i].column = points[0].column + 1;
+            points[i].row = points[0].row - 1;
+        }
+
+        if (points[i].column > 63 || points[i].row > 63)
+        {
+            points[0].delta = i - 1;
+            break;
+        }
+
+        points[i].delta = points[0].delta - i;
+    }
+
+    for (i = 0; i < points[0].delta; i++)
+    {
+        u16 *pixel = &(*gCanvasPixels)[points[i].row * 2][points[i].column];
+
+        if (!(0x8000 & *pixel))
+        {
+            u16 red = (*pixel) & 0x1F;
+            u16 green = (*pixel >> 5) & 0x1F;
+            u16 blue = (*pixel >> 10) & 0x1F;
+
+            switch (colorType)
+            {
+            case 0:
+            case 1:
+                switch (((gPointillismPoints[arg0][2] >> 3) & 7) % 3)
+                {
+                case 0:
+                    if (red >= points[i].delta)
+                        red -= points[i].delta;
+                    else
+                        red = 0;
+                    break;
+                case 1:
+                    if (green >= points[i].delta)
+                        green -= points[i].delta;
+                    else
+                        green = 0;
+                    break;
+                case 2:
+                    if (blue >= points[i].delta)
+                        blue -= points[i].delta;
+                    else
+                        blue = 0;
+                    break;
+                }
+                break;
+            case 2:
+            case 3:
+                red += points[i].delta;
+                green += points[i].delta;
+                blue += points[i].delta;
+                if (red > 31)
+                    red = 31;
+                if (green > 31)
+                    green = 31;
+                if (blue > 31)
+                    blue = 31;
+                break;
+            }
+
+            *pixel = RGB2(red, green, blue);
+        }
+    }
+}
+
+static u16 ConvertColorToGrayscale(u16 *color)
+{
+    s32 clr = *color;
+    s32 r = clr & 0x1F;
+    s32 g = (clr >> 5) & 0x1F;
+    s32 b = (clr >> 10) & 0x1F;
+    s32 gray = (r * Q_8_8(0.3) + g * Q_8_8(0.59) + b * Q_8_8(0.1133)) >> 8;
+    return RGB2(gray, gray, gray);
+}
+
+// The dark colors are the colored edges of the Cool painting effect.
+// Everything else is white.
+static u16 QuantizePixel_PersonalityColor(u16 *color, u8 personality)
+{
+    u16 red = *color & 0x1F;
+    u16 green = (*color >> 5) & 0x1F;
+    u16 blue = (*color >> 10) & 0x1F;
+
+    if (red < 17 && green < 17 && blue < 17)
+        return GetColorFromPersonality(personality);
+    else
+        return RGB_WHITE;
+}
+
+// Based on the given value, which comes from the first 8 bits of
+// the mon's personality value, return a color.
+static u16 GetColorFromPersonality(u8 personality)
+{
+    u16 red = 0;
+    u16 green = 0;
+    u16 blue = 0;
+    u8 strength = (personality / 6) % 3;
+    u8 colorType = personality % 6;
+
+    switch (colorType)
+    {
+    case 0:
+        // Teal color
+        green = 21 - strength;
+        blue = green;
+        red = 0;
+        break;
+    case 1:
+        // Yellow color
+        blue = 0;
+        red = 21 - strength;
+        green = red;
+        break;
+    case 2:
+        // Purple color
+        blue = 21 - strength;
+        green = 0;
+        red = blue;
+        break;
+    case 3:
+        // Red color
+        blue = 0;
+        green = 0;
+        red = 23 - strength;
+        break;
+    case 4:
+        // Blue color
+        blue = 23 - strength;
+        green = 0;
+        red = 0;
+        break;
+    case 5:
+        // Green color
+        blue = 0;
+        green = 23 - strength;
+        red = 0;
+        break;
+    }
+
+    return RGB2(red, green, blue);
+}
+
+static u16 QuantizePixel_BlackAndWhite(u16 *color)
+{
+    u16 red = *color & 0x1F;
+    u16 green = (*color >> 5) & 0x1F;
+    u16 blue = (*color >> 10) & 0x1F;
+
+    if (red < 17 && green < 17 && blue < 17)
+        return RGB_BLACK;
+    else
+        return RGB_WHITE;
+}
+
+static u16 QuantizePixel_BlackOutline(u16 *pixelA, u16 *pixelB)
+{
+    if (*pixelA != RGB_BLACK)
+    {
+        if (*pixelA & 0x8000)
+            return 0x8000;
+        if (*pixelB & 0x8000)
+            return RGB_BLACK;
+
+        return *pixelA;
+    }
+
+    return RGB_BLACK;
+}
+
+static u16 QuantizePixel_Invert(u16 *color)
+{
+    u16 red = *color & 0x1F;
+    u16 green = (*color >> 5) & 0x1F;
+    u16 blue = (*color >> 10) & 0x1F;
+
+    red = 31 - red;
+    green = 31 - green;
+    blue = 31 - blue;
+
+    return RGB2(red, green, blue);
+}
+
+static u16 QuantizePixel_MotionBlur(u16 *prevPixel, u16 *curPixel)
+{
+    u16 pixelChannels[2][3];
+    u16 diffs[3];
+    u8 i;
+    u16 largestDiff;
+    u16 red, green, blue;
+
+    if (*prevPixel == *curPixel)
+        return *curPixel;
+
+    pixelChannels[0][0] = (*prevPixel >> 0)  & 0x1F;
+    pixelChannels[0][1] = (*prevPixel >> 5)  & 0x1F;
+    pixelChannels[0][2] = (*prevPixel >> 10) & 0x1F;
+    pixelChannels[1][0] = (*curPixel  >> 0)  & 0x1F;
+    pixelChannels[1][1] = (*curPixel  >> 5)  & 0x1F;
+    pixelChannels[1][2] = (*curPixel  >> 10) & 0x1F;
+
+    // Don't blur light colors.
+    if (pixelChannels[0][0] > 25 && pixelChannels[0][1] > 25 && pixelChannels[0][2] > 25)
+        return *curPixel;
+    if (pixelChannels[1][0] > 25 && pixelChannels[1][1] > 25 && pixelChannels[1][2] > 25)
+        return *curPixel;
+
+    for (i = 0; i < 3; i++)
+    {
+        if (pixelChannels[0][i] > pixelChannels[1][i])
+            diffs[i] = pixelChannels[0][i] - pixelChannels[1][i];
+        else
+            diffs[i] = pixelChannels[1][i] - pixelChannels[0][i];
+    }
+
+    // Find the largest diff of any of the color channels.
+    if (diffs[0] >= diffs[1])
+    {
+        if (diffs[0] >= diffs[2])
+            largestDiff = diffs[0];
+        else if (diffs[1] >= diffs[2])
+            largestDiff = diffs[1];
+        else
+            largestDiff = diffs[2];
+    }
+    else
+    {
+        if (diffs[1] >= diffs[2])
+            largestDiff = diffs[1];
+        else if (diffs[2] >= diffs[0])
+            largestDiff = diffs[2];
+        else
+            largestDiff = diffs[0];
+    }
+
+    red =   (pixelChannels[1][0] * (31 - largestDiff / 2)) / 31;
+    green = (pixelChannels[1][1] * (31 - largestDiff / 2)) / 31;
+    blue =  (pixelChannels[1][2] * (31 - largestDiff / 2)) / 31;
+    return RGB2(red, green, blue);
+}
+
+static u16 QuantizePixel_Blur(u16 *prevPixel, u16 *curPixel, u16 *nextPixel)
+{
+    u16 red, green, blue;
+    u16 prevAvg, curAvg, nextAvg;
+    u16 prevDiff, nextDiff;
+    u32 diff;
+    u16 factor;
+
+    if (*prevPixel == *curPixel && *nextPixel == *curPixel)
+        return *curPixel;
+
+    red   = (*curPixel >> 0)  & 0x1F;
+    green = (*curPixel >> 5)  & 0x1F;
+    blue  = (*curPixel >> 10) & 0x1F;
+
+    prevAvg = (((*prevPixel >> 0) & 0x1F) + ((*prevPixel >> 5) & 0x1F) + ((*prevPixel >> 10) & 0x1F)) / 3;
+    curAvg  = (((*curPixel  >> 0) & 0x1F) + ((*curPixel  >> 5) & 0x1F) + ((*curPixel  >> 10) & 0x1F)) / 3;
+    nextAvg = (((*nextPixel >> 0) & 0x1F) + ((*nextPixel >> 5) & 0x1F) + ((*nextPixel >> 10) & 0x1F)) / 3;
+
+    if (prevAvg == curAvg && nextAvg == curAvg)
+        return *curPixel;
+
+    if (prevAvg > curAvg)
+        prevDiff = prevAvg - curAvg;
+    else
+        prevDiff = curAvg - prevAvg;
+
+    if (nextAvg > curAvg)
+        nextDiff = nextAvg - curAvg;
+    else
+        nextDiff = curAvg - nextAvg;
+
+    if (prevDiff >= nextDiff)
+        diff = prevDiff;
+    else
+        diff = nextDiff;
+
+    factor = 31 - diff / 2;
+    red   = (red   * factor) / 31;
+    green = (green * factor) / 31;
+    blue  = (blue  * factor) / 31;
+    return RGB2(red, green, blue);
+}
+
+static u16 QuantizePixel_BlurHard(u16 *prevPixel, u16 *curPixel, u16 *nextPixel)
+{
+    u16 red, green, blue;
+    u16 prevAvg, curAvg, nextAvg;
+    u16 prevDiff, nextDiff;
+    u32 diff;
+    u16 factor;
+
+    if (*prevPixel == *curPixel && *nextPixel == *curPixel)
+        return *curPixel;
+
+    red   = (*curPixel >> 0)  & 0x1F;
+    green = (*curPixel >> 5)  & 0x1F;
+    blue  = (*curPixel >> 10) & 0x1F;
+
+    prevAvg = (((*prevPixel >> 0) & 0x1F) + ((*prevPixel >> 5) & 0x1F) + ((*prevPixel >> 10) & 0x1F)) / 3;
+    curAvg  = (((*curPixel  >> 0) & 0x1F) + ((*curPixel  >> 5) & 0x1F) + ((*curPixel  >> 10) & 0x1F)) / 3;
+    nextAvg = (((*nextPixel >> 0) & 0x1F) + ((*nextPixel >> 5) & 0x1F) + ((*nextPixel >> 10) & 0x1F)) / 3;
+
+    if (prevAvg == curAvg && nextAvg == curAvg)
+        return *curPixel;
+
+    if (prevAvg > curAvg)
+        prevDiff = prevAvg - curAvg;
+    else
+        prevDiff = curAvg - prevAvg;
+
+    if (nextAvg > curAvg)
+        nextDiff = nextAvg - curAvg;
+    else
+        nextDiff = curAvg - nextAvg;
+
+    if (prevDiff >= nextDiff)
+        diff = prevDiff;
+    else
+        diff = nextDiff;
+
+    factor = 31 - diff;
+    red   = (red   * factor) / 31;
+    green = (green * factor) / 31;
+    blue  = (blue  * factor) / 31;
+    return RGB2(red, green, blue);
+}
+
+void ConvertImageProcessingToGBA(struct ImageProcessingContext *context)
+{
+    u16 i, j, k;
+    u16 *src, *dest, *src_, *dest_;
+    u16 width, height;
+
+    width = context->canvasWidth >> 3;
+    height = context->canvasHeight >> 3;
+    src_ = context->canvasPixels;
+    dest_ = context->dest;
+
+    if (context->var_16 == 2)
+    {
+        for (i = 0; i < height; i++)
+        {
+            for (j = 0; j < width; j++)
+            {
+                for (k = 0; k < 8; k++)
+                {
+                    dest = dest_ + ((i * width + j) << 5) + (k << 2);
+                    src = src_ + ((((i << 3) + k) << 3) * width) + (j << 3);
+
+                    dest[0] = src[0] | (src[1] << 8);
+                    dest[1] = src[2] | (src[3] << 8);
+                    dest[2] = src[4] | (src[5] << 8);
+                    dest[3] = src[6] | (src[7] << 8);
+                }
+            }
+        }
+    }
+    else
+    {
+        for (i = 0; i < height; i++)
+        {
+            for (j = 0; j < width; j++)
+            {
+                for (k = 0; k < 8; k++)
+                {
+                    dest = dest_ + ((i * width + j) << 4) + (k << 1);
+                    src = src_ + ((((i << 3) + k) << 3) * width) + (j << 3);
+
+                    dest[0] = src[0] | (src[1] << 4) | (src[2] << 8) | (src[3] << 0xC);
+                    dest[1] = src[4] | (src[5] << 4) | (src[6] << 8) | (src[7] << 0xC);
+                }
+            }
+        }
+    }
+}
+
+void ApplyImageProcessingQuantization(struct ImageProcessingContext *context)
+{
+    gCanvasPaletteStart = context->paletteStart * 16;
+    gCanvasPalette = &context->canvasPalette[gCanvasPaletteStart];
+    gCanvasPixels = context->canvasPixels;
+    gCanvasColumnStart = context->columnStart;
+    gCanvasRowStart = context->rowStart;
+    gCanvasColumnEnd = context->columnEnd;
+    gCanvasRowEnd = context->rowEnd;
+    gCanvasWidth = context->canvasWidth;
+    gCanvasHeight = context->canvasHeight;
+
+    switch (context->quantizeEffect)
+    {
+    case QUANTIZE_EFFECT_STANDARD:
+        QuantizePalette_Standard(FALSE);
+        break;
+    case QUANTIZE_EFFECT_STANDARD_LIMITED_COLORS:
+        QuantizePalette_Standard(TRUE);
+        break;
+    case QUANTIZE_EFFECT_PRIMARY_COLORS:
+        SetPresetPalette_PrimaryColors();
+        QuantizePalette_PrimaryColors();
+        break;
+    case QUANTIZE_EFFECT_GRAYSCALE:
+        SetPresetPalette_Grayscale();
+        QuantizePalette_Grayscale();
+        break;
+    case QUANTIZE_EFFECT_GRAYSCALE_SMALL:
+        SetPresetPalette_GrayscaleSmall();
+        QuantizePalette_GrayscaleSmall();
+        break;
+    case QUANTIZE_EFFECT_BLACK_WHITE:
+        SetPresetPalette_BlackAndWhite();
+        QuantizePalette_BlackAndWhite();
+        break;
+    }
+}
+
+static void SetPresetPalette_PrimaryColors(void)
+{
+    gCanvasPalette[0]  = RGB2(0, 0, 0);
+    gCanvasPalette[1]  = RGB2(6, 6, 6);
+    gCanvasPalette[2]  = RGB2(29, 29, 29);
+    gCanvasPalette[3]  = RGB2(11, 11, 11);
+    gCanvasPalette[4]  = RGB2(29, 6, 6);
+    gCanvasPalette[5]  = RGB2(6, 29, 6);
+    gCanvasPalette[6]  = RGB2(6, 6, 29);
+    gCanvasPalette[7]  = RGB2(29, 29, 6);
+    gCanvasPalette[8]  = RGB2(29, 6, 29);
+    gCanvasPalette[9]  = RGB2(6, 29, 29);
+    gCanvasPalette[10] = RGB2(29, 11, 6);
+    gCanvasPalette[11] = RGB2(11, 29, 6);
+    gCanvasPalette[12] = RGB2(6, 11, 29);
+    gCanvasPalette[13] = RGB2(29, 6, 11);
+    gCanvasPalette[14] = RGB2(6, 29, 11);
+    gCanvasPalette[15] = RGB2(11, 6, 29);
+}
+
+static void SetPresetPalette_BlackAndWhite(void)
+{
+    gCanvasPalette[0] = RGB2(0, 0, 0);
+    gCanvasPalette[1] = RGB2(0, 0, 0);
+    gCanvasPalette[2] = RGB2(31, 31, 31);
+}
+
+static void SetPresetPalette_GrayscaleSmall(void)
+{
+    u8 i;
+
+    gCanvasPalette[0] = RGB2(0, 0, 0);
+    gCanvasPalette[1] = RGB2(0, 0, 0);
+    for (i = 0; i < 14; i++)
+        gCanvasPalette[i + 2] = RGB2(2 * (i + 2), 2 * (i + 2), 2 * (i + 2));
+}
+
+static void SetPresetPalette_Grayscale(void)
+{
+    u8 i;
+
+    gCanvasPalette[0] = RGB2(0, 0, 0);
+    for (i = 0; i < 32; i++)
+        gCanvasPalette[i + 1] = RGB2(i, i, i);
+}
+
+static void QuantizePalette_Standard(bool8 useLimitedPalette)
+{
+    u8 i, j;
+    u16 maxIndex;
+
+    maxIndex = 0xDF;
+    if (!useLimitedPalette)
+        maxIndex = 0xFF;
+
+    for (i = 0; i < maxIndex; i++)
+        gCanvasPalette[i] = RGB_BLACK;
+
+    gCanvasPalette[maxIndex] = RGB2(15, 15, 15);
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
+        {
+            if (*pixel & 0x8000)
+            {
+                *pixel = gCanvasPaletteStart;
+            }
+            else
+            {
+                u16 quantizedColor = QuantizePixel_Standard(pixel);
+                u8 curIndex = 1;
+                if (curIndex < maxIndex)
+                {
+                    if (gCanvasPalette[curIndex] == RGB_BLACK)
+                    {
+                        // The quantized color does not match any existing color in the
+                        // palette, so we add it to the palette.
+                        // This if block seems pointless because the below while loop handles
+                        // this same logic.
+                        gCanvasPalette[curIndex] = quantizedColor;
+                        *pixel = gCanvasPaletteStart + curIndex;
+                    }
+                    else
+                    {
+                        while (curIndex < maxIndex)
+                        {
+                            if (gCanvasPalette[curIndex] == RGB_BLACK)
+                            {
+                                // The quantized color does not match any existing color in the
+                                // palette, so we add it to the palette.
+                                gCanvasPalette[curIndex] = quantizedColor;
+                                *pixel = gCanvasPaletteStart + curIndex;
+                                break;
+                            }
+
+                            if (gCanvasPalette[curIndex] == quantizedColor)
+                            {
+                                // The quantized color matches this existing color in the
+                                // palette, so we use this existing color for the pixel.
+                                *pixel = gCanvasPaletteStart + curIndex;
+                                break;
+                            }
+
+                            curIndex++;
+                        }
+                    }
+                }
+
+                if (curIndex == maxIndex)
+                {
+                    // The entire palette's colors are already in use, which means
+                    // the base image has too many colors to handle. This error is handled
+                    // by marking such pixels as gray color.
+                    curIndex = maxIndex;
+                    *pixel = curIndex;
+                }
+            }
+        }
+    }
+}
+
+static void QuantizePalette_BlackAndWhite(void)
+{
+    u8 i, j;
+
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
+        {
+            if (*pixel & 0x8000)
+            {
+                *pixel = gCanvasPaletteStart;
+            }
+            else
+            {
+                if (QuantizePixel_BlackAndWhite(pixel) == RGB_BLACK)
+                {
+                    // Black is the first color in the quantized palette.
+                    *pixel = gCanvasPaletteStart + 1;
+                }
+                else
+                {
+                    // White is the second color in the quantized palette.
+                    *pixel = gCanvasPaletteStart + 2;
+                }
+            }
+        }
+    }
+}
+
+static void QuantizePalette_GrayscaleSmall(void)
+{
+    u8 i, j;
+
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
+        {
+            if (*pixel & 0x8000)
+                *pixel = gCanvasPaletteStart;
+            else
+                *pixel = QuantizePixel_GrayscaleSmall(pixel) + gCanvasPaletteStart;
+        }
+    }
+}
+
+static void QuantizePalette_Grayscale(void)
+{
+    u8 i, j;
+
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
+        {
+            if (*pixel & 0x8000)
+                *pixel = gCanvasPaletteStart;
+            else
+                *pixel = QuantizePixel_Grayscale(pixel) + gCanvasPaletteStart;
+        }
+    }
+}
+
+static void QuantizePalette_PrimaryColors(void)
+{
+    u8 i, j;
+
+    for (j = 0; j < gCanvasRowEnd; j++)
+    {
+        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixel = &pixelRow[gCanvasColumnStart];
+        for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
+        {
+            if (*pixel & 0x8000)
+                *pixel = gCanvasPaletteStart;
+            else
+                *pixel = QuantizePixel_PrimaryColors(pixel) + gCanvasPaletteStart;
+        }
+    }
+}
+
+// Quantizes the pixel's color channels to nearest multiple of 4, and clamps to [6, 30].
+static u16 QuantizePixel_Standard(u16 *pixel)
+{
+    u16 red = *pixel & 0x1F;
+    u16 green = (*pixel >> 5) & 0x1F;
+    u16 blue = (*pixel >> 10) & 0x1F;
+
+    // Quantize color channels to muliples of 4, rounding up.
+    if (red & 3)
+        red = (red & 0x1C) + 4;
+    if (green & 3)
+        green = (green & 0x1C) + 4;
+    if (blue & 3)
+        blue = (blue & 0x1C) + 4;
+
+    // Clamp channels to [6, 30].
+    if (red < 6)
+        red = 6;
+    if (red > 30)
+        red = 30;
+    if (green < 6)
+        green = 6;
+    if (green > 30)
+        green = 30;
+    if (blue < 6)
+        blue = 6;
+    if (blue > 30)
+        blue = 30;
+
+    return RGB2(red, green, blue);
+}
+
+static u16 QuantizePixel_PrimaryColors(u16* color)
+{
+    u16 red = *color & 0x1F;
+    u16 green = (*color >> 5) & 0x1F;
+    u16 blue = (*color >> 10) & 0x1F;
+
+    if (red < 12 && green < 11 && blue < 11)
+        return 1;
+
+    if (red > 19 && green > 19 && blue > 19)
+        return 2;
+
+    if (red > 19)
+    {
+        if (green > 19)
+        {
+            if (blue > 14)
+                return 2;
+            else
+                return 7;
+        }
+        else if (blue > 19)
+        {
+            if (green > 14)
+                return 2;
+            else
+                return 8;
+        }
+    }
+
+    if (green > 19 && blue > 19)
+    {
+        if (red > 14)
+            return 2;
+        else
+            return 9;
+    }
+
+    if (red > 19)
+    {
+        if (green > 11)
+        {
+            if (blue > 11)
+            {
+                if (green < blue)
+                    return 8;
+                else
+                    return 7;
+            }
+            else
+            {
+                return 10;
+            }
+        }
+        else if (blue > 11)
+        {
+            return 13;
+        }
+        else
+        {
+            return 4;
+        }
+    }
+
+    if (green > 19)
+    {
+        if (red > 11)
+        {
+            if (blue > 11)
+            {
+                if (red < blue)
+                    return 9;
+                else
+                    return 7;
+            }
+            else
+            {
+                return 11;
+            }
+        }
+        else
+        {
+            if (blue > 11)
+                return 14;
+            else
+                return 5;
+        }
+    }
+
+    if (blue > 19)
+    {
+        if (red > 11)
+        {
+            if (green > 11)
+            {
+                if (red < green)
+                    return 9;
+                else
+                    return 8;
+            }
+        }
+        else if (green > 11)
+        {
+            return 12;
+        }
+
+        if (blue > 11)
+            return 15;
+        else
+            return 6;
+    }
+
+    return 3;
+}
+
+static u16 QuantizePixel_GrayscaleSmall(u16 *color)
+{
+    u16 red = *color & 0x1F;
+    u16 green = (*color >> 5) & 0x1F;
+    u16 blue = (*color >> 10) & 0x1F;
+    u16 average = ((red + green + blue) / 3) & 0x1E;
+    if (average == 0)
+        return 1;
+    else
+        return average / 2;
+}
+
+static u16 QuantizePixel_Grayscale(u16 *color)
+{
+    u16 red = *color & 0x1F;
+    u16 green = (*color >> 5) & 0x1F;
+    u16 blue = (*color >> 10) & 0x1F;
+    u16 average = (red + green + blue) / 3;
+    return average + 1;
+}