Reviewed function GenImagePerlinNoise()

Added support for noise image offset

examples/textures/textures_image_generation.c

@@ -24,10 +24,10 @@ int main()
 
     Image verticalGradient = GenImageGradientV(screenWidth, screenHeight, RED, BLUE);
     Image horizontalGradient = GenImageGradientH(screenWidth, screenHeight, RED, BLUE);
-    Image radialGradient = GenImageGradientRadial(screenWidth, screenHeight, 0.f, WHITE, BLACK);
+    Image radialGradient = GenImageGradientRadial(screenWidth, screenHeight, 0.0f, WHITE, BLACK);
     Image checked = GenImageChecked(screenWidth, screenHeight, 32, 32, RED, BLUE);
     Image whiteNoise = GenImageWhiteNoise(screenWidth, screenHeight, 0.5f);
-    Image perlinNoise = GenImagePerlinNoise(screenWidth, screenHeight, 8.f);
+    Image perlinNoise = GenImagePerlinNoise(screenWidth, screenHeight, 50, 50, 4.0f);
     Image cellular = GenImageCellular(screenWidth, screenHeight, 32);
 
     Texture2D textures[NUM_TEXTURES];

src/raylib.h

@@ -908,7 +908,7 @@ RLAPI Image GenImageGradientH(int width, int height, Color left, Color right);
 RLAPI Image GenImageGradientRadial(int width, int height, float density, Color inner, Color outer);      // Generate image: radial gradient
 RLAPI Image GenImageChecked(int width, int height, int checksX, int checksY, Color col1, Color col2);    // Generate image: checked
 RLAPI Image GenImageWhiteNoise(int width, int height, float factor);                                     // Generate image: white noise
-RLAPI Image GenImagePerlinNoise(int width, int height, float scale);                                     // Generate image: perlin noise
+RLAPI Image GenImagePerlinNoise(int width, int height, int offsetX, int offsetY, float scale);           // Generate image: perlin noise
 RLAPI Image GenImageCellular(int width, int height, int tileSize);                                       // Generate image: cellular algorithm. Bigger tileSize means bigger cells
 
 // Texture2D configuration functions

src/textures.c

@@ -611,6 +611,8 @@ Image ImageCopy(Image image)
         newImage.height = image.height;
         newImage.mipmaps = image.mipmaps;
         newImage.format = image.format;
+        
+        //if (image.mipmaps > 1) ImageMipmaps(&newImage);
     }
 
     return newImage;
@@ -823,6 +825,8 @@ void ImageFormat(Image *image, int newFormat)
             }
 
             free(pixels);
+            
+            //if (image->mipmaps > 1) ImageMipmaps(image);
         }
         else TraceLog(LOG_WARNING, "Image data format is compressed, can not be converted");
     }
@@ -1688,7 +1692,7 @@ Image GenImageWhiteNoise(int width, int height, float factor)
 }
 
 // Generate image: perlin noise
-Image GenImagePerlinNoise(int width, int height, float scale)
+Image GenImagePerlinNoise(int width, int height, int offsetX, int offsetY, float scale)
 {
     Color *pixels = (Color *)malloc(width*height*sizeof(Color));
 
@@ -1696,13 +1700,18 @@ Image GenImagePerlinNoise(int width, int height, float scale)
     {
         for (int x = 0; x < width; x++)
         {
-            float nx = (float)x*scale/(float)width;
-            float ny = (float)y*scale/(float)height;
+            float nx = (float)(x + offsetX)*scale/(float)width;
+            float ny = (float)(y + offsetY)*scale/(float)height;
             
-            // we need to translate the data from [-1; 1] to [0; 1]
-            float p = (stb_perlin_fbm_noise3(nx, ny, 1.0f, 2.0f, 0.5f, 6, 0, 0, 0) + 1.0f) / 2.0f;
+            // Typical values to start playing with:
+            //   lacunarity = ~2.0   -- spacing between successive octaves (use exactly 2.0 for wrapping output)
+            //   gain       =  0.5   -- relative weighting applied to each successive octave
+            //   octaves    =  6     -- number of "octaves" of noise3() to sum
+
+            // NOTE: We need to translate the data from [-1..1] to [0..1]
+            float p = (stb_perlin_fbm_noise3(nx, ny, 1.0f, 2.0f, 0.5f, 6, 0, 0, 0) + 1.0f)/2.0f;
             
-            int intensity = (int)(p * 255.0f);
+            int intensity = (int)(p*255.0f);
             pixels[y*width + x] = (Color){intensity, intensity, intensity, 255};
         }
     }