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Removed dependence of gaussian blur to box blur & Fixed precision errors

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This commit is contained in:
nobytesgiven 2022-10-25 18:43:43 +03:00
parent 1f4f26e7b0
commit 1ef6cae66e
2 changed files with 115 additions and 104 deletions
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1
src/raylib.h
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@ -1258,7 +1258,6 @@ RLAPI void ImageAlphaCrop(Image *image, float threshold);
RLAPI void ImageAlphaClear(Image *image, Color color, float threshold); // Clear alpha channel to desired color
RLAPI void ImageAlphaMask(Image *image, Image alphaMask); // Apply alpha mask to image
RLAPI void ImageAlphaPremultiply(Image *image); // Premultiply alpha channel
RLAPI void ImageBlurBox(Image *image, int blurSize); // Apply box blur
RLAPI void ImageBlurGaussian(Image *image, int blurSize); // Apply Gaussian blur using a box blur approximation
RLAPI void ImageResize(Image *image, int newWidth, int newHeight); // Resize image (Bicubic scaling algorithm)
RLAPI void ImageResizeNN(Image *image, int newWidth,int newHeight); // Resize image (Nearest-Neighbor scaling algorithm)

134
src/rtextures.c
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@ -1499,7 +1499,7 @@ void ImageAlphaPremultiply(Image *image)
}
// Apply box blur
void ImageBlurBox(Image *image, int blurSize) {
void ImageBlurGaussian(Image *image, int blurSize) {
// Security check to avoid program crash
if ((image->data == NULL) || (image->width == 0) || (image->height == 0)) return;
@ -1508,7 +1508,20 @@ void ImageBlurBox(Image *image, int blurSize) {
Color *pixels = LoadImageColors(*image);
Color *pixelsCopy = LoadImageColors(*image);
// Horizontal box blur
// Loop switches between pixelsCopy1 and pixelsCopy2
Vector4 *pixelsCopy1 = RL_MALLOC((image->height)*(image->width)*sizeof(Vector4));
Vector4 *pixelsCopy2 = RL_MALLOC((image->height)*(image->width)*sizeof(Vector4));
for (int i = 0; i < (image->height)*(image->width); i++) {
pixelsCopy1[i].x = pixels[i].r;
pixelsCopy1[i].y = pixels[i].g;
pixelsCopy1[i].z = pixels[i].b;
pixelsCopy1[i].w = pixels[i].a;
}
// Repeated convolution of rectangular window signal by itself converges to a gaussian distribution
for (int j = 0; j < GAUSSIAN_BLUR_ITERATIONS; j++) {
// Horizontal motion blur
for (int row = 0; row < image->height; row++)
{
float avgR = 0.0f;
@ -1519,45 +1532,45 @@ void ImageBlurBox(Image *image, int blurSize) {
for (int i = 0; i < blurSize+1; i++)
{
avgR += pixelsCopy[row*image->width + i].r;
avgG += pixelsCopy[row*image->width + i].g;
avgB += pixelsCopy[row*image->width + i].b;
avgAlpha += pixelsCopy[row*image->width + i].a;
avgR += pixelsCopy1[row*image->width + i].x;
avgG += pixelsCopy1[row*image->width + i].y;
avgB += pixelsCopy1[row*image->width + i].z;
avgAlpha += pixelsCopy1[row*image->width + i].w;
}
pixels[row*image->width].r = (unsigned char) (avgR/convolutionSize);
pixels[row*image->width].g = (unsigned char) (avgG/convolutionSize);
pixels[row*image->width].b = (unsigned char) (avgB/convolutionSize);
pixels[row*image->width].a = (unsigned char) (avgAlpha/convolutionSize);
pixelsCopy2[row*image->width].x = avgR/convolutionSize;
pixelsCopy2[row*image->width].y = avgG/convolutionSize;
pixelsCopy2[row*image->width].z = avgB/convolutionSize;
pixelsCopy2[row*image->width].w = avgAlpha/convolutionSize;
for (int x = 1; x < image->width; x++)
{
if (x-blurSize >= 0)
{
avgR -= pixelsCopy[row*image->width + x-blurSize].r;
avgG -= pixelsCopy[row*image->width + x-blurSize].g;
avgB -= pixelsCopy[row*image->width + x-blurSize].b;
avgAlpha -= pixelsCopy[row*image->width + x-blurSize].a;
avgR -= pixelsCopy1[row*image->width + x-blurSize].x;
avgG -= pixelsCopy1[row*image->width + x-blurSize].y;
avgB -= pixelsCopy1[row*image->width + x-blurSize].z;
avgAlpha -= pixelsCopy1[row*image->width + x-blurSize].w;
convolutionSize--;
}
if (x+blurSize < image->width)
{
avgR += pixelsCopy[row*image->width + x+blurSize].r;
avgG += pixelsCopy[row*image->width + x+blurSize].g;
avgB += pixelsCopy[row*image->width + x+blurSize].b;
avgAlpha += pixelsCopy[row*image->width + x+blurSize].a;
avgR += pixelsCopy1[row*image->width + x+blurSize].x;
avgG += pixelsCopy1[row*image->width + x+blurSize].y;
avgB += pixelsCopy1[row*image->width + x+blurSize].z;
avgAlpha += pixelsCopy1[row*image->width + x+blurSize].w;
convolutionSize++;
}
pixels[row*image->width + x].r = (unsigned char) (avgR/convolutionSize);
pixels[row*image->width + x].g = (unsigned char) (avgG/convolutionSize);
pixels[row*image->width + x].b = (unsigned char) (avgB/convolutionSize);
pixels[row*image->width + x].a = (unsigned char) (avgAlpha/convolutionSize);
pixelsCopy2[row*image->width + x].x = avgR/convolutionSize;
pixelsCopy2[row*image->width + x].y = avgG/convolutionSize;
pixelsCopy2[row*image->width + x].z = avgB/convolutionSize;
pixelsCopy2[row*image->width + x].w = avgAlpha/convolutionSize;
}
}
// Vertical box blur
// Vertical motion blur
for (int col = 0; col < image->width; col++)
{
float avgR = 0.0f;
@ -1568,77 +1581,76 @@ void ImageBlurBox(Image *image, int blurSize) {
for (int i = 0; i < blurSize+1; i++)
{
avgR += pixels[i*image->width + col].r;
avgG += pixels[i*image->width + col].g;
avgB += pixels[i*image->width + col].b;
avgAlpha += pixels[i*image->width + col].a;
avgR += pixelsCopy2[i*image->width + col].x;
avgG += pixelsCopy2[i*image->width + col].y;
avgB += pixelsCopy2[i*image->width + col].z;
avgAlpha += pixelsCopy2[i*image->width + col].w;
}
pixelsCopy[col].r = (unsigned char) (avgR/convolutionSize);
pixelsCopy[col].g = (unsigned char) (avgG/convolutionSize);
pixelsCopy[col].b = (unsigned char) (avgB/convolutionSize);
pixelsCopy[col].a = (unsigned char) (avgAlpha/convolutionSize);
pixelsCopy1[col].x = (unsigned char) (avgR/convolutionSize);
pixelsCopy1[col].y = (unsigned char) (avgG/convolutionSize);
pixelsCopy1[col].z = (unsigned char) (avgB/convolutionSize);
pixelsCopy1[col].w = (unsigned char) (avgAlpha/convolutionSize);
for (int y = 1; y < image->height; y++)
{
if (y-blurSize >= 0)
{
avgR -= pixels[(y-blurSize)*image->width + col].r;
avgG -= pixels[(y-blurSize)*image->width + col].g;
avgB -= pixels[(y-blurSize)*image->width + col].b;
avgAlpha -= pixels[(y-blurSize)*image->width + col].a;
avgR -= pixelsCopy2[(y-blurSize)*image->width + col].x;
avgG -= pixelsCopy2[(y-blurSize)*image->width + col].y;
avgB -= pixelsCopy2[(y-blurSize)*image->width + col].z;
avgAlpha -= pixelsCopy2[(y-blurSize)*image->width + col].w;
convolutionSize--;
}
if (y+blurSize < image->height)
{
avgR += pixels[(y+blurSize)*image->width + col].r;
avgG += pixels[(y+blurSize)*image->width + col].g;
avgB += pixels[(y+blurSize)*image->width + col].b;
avgAlpha += pixels[(y+blurSize)*image->width + col].a;
avgR += pixelsCopy2[(y+blurSize)*image->width + col].x;
avgG += pixelsCopy2[(y+blurSize)*image->width + col].y;
avgB += pixelsCopy2[(y+blurSize)*image->width + col].z;
avgAlpha += pixelsCopy2[(y+blurSize)*image->width + col].w;
convolutionSize++;
}
pixelsCopy[y*image->width + col].r = (unsigned char) (avgR/convolutionSize);
pixelsCopy[y*image->width + col].g = (unsigned char) (avgG/convolutionSize);
pixelsCopy[y*image->width + col].b = (unsigned char) (avgB/convolutionSize);
pixelsCopy[y*image->width + col].a = (unsigned char) (avgAlpha/convolutionSize);
pixelsCopy1[y*image->width + col].x = (unsigned char) (avgR/convolutionSize);
pixelsCopy1[y*image->width + col].y = (unsigned char) (avgG/convolutionSize);
pixelsCopy1[y*image->width + col].z = (unsigned char) (avgB/convolutionSize);
pixelsCopy1[y*image->width + col].w = (unsigned char) (avgAlpha/convolutionSize);
}
}
}
// Reverse premultiply
for (int i = 0; i < image->width*image->height; i++)
for (int i = 0; i < (image->width)*(image->height); i++)
{
if (pixelsCopy[i].a == 0)
if (pixelsCopy1[i].w == 0)
{
pixelsCopy[i].r = 0;
pixelsCopy[i].g = 0;
pixelsCopy[i].b = 0;
pixels[i].r = 0;
pixels[i].g = 0;
pixels[i].b = 0;
pixels[i].a = 0;
}
else if (pixelsCopy[i].a < 255)
else if (pixelsCopy1[i].w < 255.0f)
{
float alpha = (float)pixelsCopy[i].a/255.0f;
pixelsCopy[i].r = (unsigned char)((float)pixelsCopy[i].r/alpha);
pixelsCopy[i].g = (unsigned char)((float)pixelsCopy[i].g/alpha);
pixelsCopy[i].b = (unsigned char)((float)pixelsCopy[i].b/alpha);
float alpha = (float)pixelsCopy1[i].w/255.0f;
pixels[i].r = (unsigned char)((float)pixelsCopy1[i].x/alpha);
pixels[i].g = (unsigned char)((float)pixelsCopy1[i].y/alpha);
pixels[i].b = (unsigned char)((float)pixelsCopy1[i].z/alpha);
pixels[i].a = (unsigned char) pixelsCopy1[i].w;
}
}
int format = image->format;
RL_FREE(image->data);
RL_FREE(pixelsCopy1);
RL_FREE(pixelsCopy2);
UnloadImageColors(pixels);
image->data = pixelsCopy;
image->data = pixels;
image->format = PIXELFORMAT_UNCOMPRESSED_R8G8B8A8;
ImageFormat(image, format);
}
void ImageBlurGaussian(Image *image, int blurSize)
{
for (int i = 0; i < GAUSSIAN_BLUR_ITERATIONS; i++) ImageBlurBox(image, blurSize);
}
// Resize and image to new size
// NOTE: Uses stb default scaling filters (both bicubic):
// STBIR_DEFAULT_FILTER_UPSAMPLE STBIR_FILTER_CATMULLROM