REVIEWED: LoadImageFromTexture() for Wasm https://github.com/raysan5/rguistyler/issues/10

Let's see if it breaks on some other platform...

src/rlgl.h

@@ -3777,9 +3777,17 @@ void *rlReadTexturePixels(unsigned int id, int width, int height, int format)
     // Attach our texture to FBO
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, id, 0);
 
+#if defined(FBO_READ_TEXTURE_AS_RGBA)
     // Reading data as RGBA because FBO texture is configured as RGBA, despite binding another texture format
     pixels = RL_CALLOC(rlGetPixelDataSize(width, height, RL_PIXELFORMAT_UNCOMPRESSED_R8G8B8A8), 1);
     glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+#else
+    // Reading data as original texture format, in some platforms (RPI, Wasm) it works
+    pixels = (unsigned char *)RL_MALLOC(GetPixelDataSize(texture.width, texture.height, texture.format));
+    unsigned int glInternalFormat = 0, glFormat = 0, glType = 0;
+    rlGetGlTextureFormats(texture.format, &glInternalFormat, &glFormat, &glType);
+    glReadPixels(0, 0, texture.width, texture.height, glFormat, glType, pixels);
+#endif
 
     glBindFramebuffer(GL_FRAMEBUFFER, 0);
 

src/rtextures.c

@@ -562,15 +562,18 @@ Image LoadImageFromTexture(Texture2D texture)
         {
             image.width = texture.width;
             image.height = texture.height;
-            image.format = texture.format;
+#if defined(FBO_READ_TEXTURE_AS_RGBA)
-            image.mipmaps = 1;
+            // WARNING: On OpenGL ES 2.0/WebGL 1.0, there is no glGetTexImage() so,
-
+            // texture data is retrieved by creating an RGBA fbo, binding the texture
-#if defined(GRAPHICS_API_OPENGL_ES2)
+            // to the fbo color attachment, and reading it as RGBA data with glReadPixels()
-            // NOTE: Data retrieved on OpenGL ES 2.0 should be RGBA,
+            // Returned data *should* be RGBA but it seems on some platforms (RPI, WASM)
-            // coming from FBO color buffer attachment, but it seems
+            // original texture format is retrieved, so adding a define for this patch
-            // original texture format is retrieved on RPI...
             image.format = PIXELFORMAT_UNCOMPRESSED_R8G8B8A8;
+#else
+            image.format = texture.format;
 #endif
+            image.mipmaps = 1;
+                        
             TRACELOG(LOG_INFO, "TEXTURE: [ID %i] Pixel data retrieved successfully", texture.id);
         }
         else TRACELOG(LOG_WARNING, "TEXTURE: [ID %i] Failed to retrieve pixel data", texture.id);