ADDED: UpdateTextureRec()

src/raylib.h

@@ -1172,6 +1172,7 @@ RLAPI RenderTexture2D LoadRenderTexture(int width, int height);
 RLAPI void UnloadTexture(Texture2D texture);                                                             // Unload texture from GPU memory (VRAM)
 RLAPI void UnloadRenderTexture(RenderTexture2D target);                                                  // Unload render texture from GPU memory (VRAM)
 RLAPI void UpdateTexture(Texture2D texture, const void *pixels);                                         // Update GPU texture with new data
+RLAPI void UpdateTextureRec(Texture2D texture, Rectangle rec, const void *pixels);                       // Update GPU texture rectangle with new data
 RLAPI Image GetTextureData(Texture2D texture);                                                           // Get pixel data from GPU texture and return an Image
 RLAPI Image GetScreenData(void);                                                                         // Get pixel data from screen buffer and return an Image (screenshot)
 

src/rlgl.h

@@ -528,7 +528,7 @@ RLAPI Vector3 rlUnproject(Vector3 source, Matrix proj, Matrix view);  // Get wor
 RLAPI unsigned int rlLoadTexture(void *data, int width, int height, int format, int mipmapCount); // Load texture in GPU
 RLAPI unsigned int rlLoadTextureDepth(int width, int height, int bits, bool useRenderBuffer);     // Load depth texture/renderbuffer (to be attached to fbo)
 RLAPI unsigned int rlLoadTextureCubemap(void *data, int size, int format);                        // Load texture cubemap
-RLAPI void rlUpdateTexture(unsigned int id, int width, int height, int format, const void *data); // Update GPU texture with new data
+RLAPI void rlUpdateTexture(unsigned int id, int offsetX, int offsetY, int width, int height, int format, const void *data);  // Update GPU texture with new data
 RLAPI void rlGetGlTextureFormats(int format, unsigned int *glInternalFormat, unsigned int *glFormat, unsigned int *glType);  // Get OpenGL internal formats
 RLAPI void rlUnloadTexture(unsigned int id);                              // Unload texture from GPU memory
 
@@ -2144,7 +2144,7 @@ unsigned int rlLoadTextureCubemap(void *data, int size, int format)
 
 // Update already loaded texture in GPU with new data
 // NOTE: We don't know safely if internal texture format is the expected one...
-void rlUpdateTexture(unsigned int id, int width, int height, int format, const void *data)
+void rlUpdateTexture(unsigned int id, int offsetX, int offsetY, int width, int height, int format, const void *data)
 {
     glBindTexture(GL_TEXTURE_2D, id);
 
@@ -2153,7 +2153,7 @@ void rlUpdateTexture(unsigned int id, int width, int height, int format, const v
 
     if ((glInternalFormat != -1) && (format < COMPRESSED_DXT1_RGB))
     {
-        glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, glFormat, glType, (unsigned char *)data);
+        glTexSubImage2D(GL_TEXTURE_2D, 0, offsetY, offsetY, width, height, glFormat, glType, (unsigned char *)data);
     }
     else TRACELOG(LOG_WARNING, "TEXTURE: [ID %i] Failed to update for current texture format (%i)", id, format);
 }

src/textures.c

@@ -2798,7 +2798,14 @@ void UnloadRenderTexture(RenderTexture2D target)
 // NOTE: pixels data must match texture.format
 void UpdateTexture(Texture2D texture, const void *pixels)
 {
-    rlUpdateTexture(texture.id, texture.width, texture.height, texture.format, pixels);
+    rlUpdateTexture(texture.id, 0, 0, texture.width, texture.height, texture.format, pixels);
+}
+
+// Update GPU texture rectangle with new data
+// NOTE: pixels data must match texture.format
+void UpdateTextureRec(Texture2D texture, Rectangle rec, const void *pixels)
+{
+    rlUpdateTexture(texture.id, (int)rec.x, (int)rec.y, (int)rec.width, (int)rec.height, texture.format, pixels);
 }
 
 // Get pixel data from GPU texture and return an Image