Image convolution function ImageKernelConvolution (#3528)

* Added image convultion ImageKernelConvolution

* comment changes

* spelling changes and change to kernel size

* removed kernel normalization inside function

* fix to formating

2 files changed, 128 insertions, 0 deletions

diff --git a/examples/Makefile b/examples/Makefile
index 5cd8e6bb..11669e3a 100644
--- a/examples/Makefile
+++ b/examples/Makefile
@@ -490,6 +490,7 @@ TEXTURES = \
     textures/textures_gif_player \
     textures/textures_image_drawing \
     textures/textures_image_generation \
+    textures/textures_image_kernel \
     textures/textures_image_loading \
     textures/textures_image_processing \
     textures/textures_image_rotate \
diff --git a/examples/textures/textures_image_kernel.c b/examples/textures/textures_image_kernel.c
new file mode 100644
index 00000000..cbc75e18
--- /dev/null
+++ b/examples/textures/textures_image_kernel.c
@@ -0,0 +1,127 @@
+/*******************************************************************************************
+*
+*   raylib [textures] example - Image loading and texture creation
+*
+*   NOTE: Images are loaded in CPU memory (RAM); textures are loaded in GPU memory (VRAM)
+*
+*   Example originally created with raylib 1.3, last time updated with raylib 1.3
+*
+*   Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
+*   BSD-like license that allows static linking with closed source software
+*
+*   Copyright (c) 2015-2023 Karim Salem (@kimo-s)
+*
+********************************************************************************************/
+
+#include "raylib.h"
+
+//------------------------------------------------------------------------------------
+// Program main entry point
+//------------------------------------------------------------------------------------
+void normalizeKernel(float *kernel, int size){
+    float sum = 0.0f;
+    for(int i = 0; i < size; i++)
+    {
+        sum += kernel[i]; 
+    }
+
+    if(sum != 0.0f)
+    {
+        for(int i = 0; i < size; i++)
+        {
+            kernel[i] /= sum; 
+        }
+    }
+}
+
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+
+    Image image = LoadImage("resources/cat.png");     // Loaded in CPU memory (RAM)
+
+    const int screenWidth = 800;
+    const int screenHeight = 450;
+
+    InitWindow(screenWidth, screenHeight, "raylib [textures] example - image convolution");
+
+    float gaussiankernel[] = {1.0, 2.0, 1.0,
+                    2.0, 4.0, 2.0,
+                    1.0, 2.0, 1.0};
+
+    float sobelkernel[] = {1.0, 0.0, -1.0,
+                    2.0, 0.0, -2.0,
+                    1.0, 0.0, -1.0};
+
+    float sharpenkernel[] = {0.0, -1.0, 0.0,
+                        -1.0, 5.0, -1.0,
+                        0.0, -1.0, 0.0};
+
+    normalizeKernel(gaussiankernel, 9);
+    normalizeKernel(sharpenkernel, 9);
+    normalizeKernel(sobelkernel, 9);
+
+    Image catSharpend = ImageCopy(image);
+    ImageKernelConvolution(&catSharpend, sharpenkernel, 9);
+ 
+    Image catSobel = ImageCopy(image);
+    ImageKernelConvolution(&catSobel, sobelkernel, 9);
+
+    Image catGaussian = ImageCopy(image);
+    for(int i = 0; i < 6; i++)
+    {
+        ImageKernelConvolution(&catGaussian, gaussiankernel, 9);
+    }
+
+    ImageCrop(&image, (Rectangle){ 0, 0, (float)200, (float)450 });
+    ImageCrop(&catGaussian, (Rectangle){ 0, 0, (float)200, (float)450 });
+    ImageCrop(&catSobel, (Rectangle){ 0, 0, (float)200, (float)450 });
+    ImageCrop(&catSharpend, (Rectangle){ 0, 0, (float)200, (float)450 });
+    Texture2D texture = LoadTextureFromImage(image);          // Image converted to texture, GPU memory (VRAM)
+    Texture2D catSharpendTexture = LoadTextureFromImage(catSharpend);
+    Texture2D catSobelTexture = LoadTextureFromImage(catSobel);
+    Texture2D catGaussianTexture = LoadTextureFromImage(catGaussian);
+    UnloadImage(image);   // Once image has been converted to texture and uploaded to VRAM, it can be unloaded from RAM
+    UnloadImage(catGaussian);
+    UnloadImage(catSobel);
+    UnloadImage(catSharpend);
+
+    SetTargetFPS(60);     // Set our game to run at 60 frames-per-second
+    //---------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        // TODO: Update your variables here
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+            ClearBackground(RAYWHITE);
+
+            DrawTexture(catSharpendTexture, 0, 0, WHITE);
+            DrawTexture(catSobelTexture, 200, 0, WHITE);
+            DrawTexture(catGaussianTexture, 400, 0, WHITE);
+            DrawTexture(texture, 600, 0, WHITE);
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    UnloadTexture(texture);       // Texture unloading
+    UnloadTexture(catGaussianTexture);
+    UnloadTexture(catSobelTexture);
+    UnloadTexture(catSharpendTexture);
+
+    CloseWindow();                // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}