[rtextures/rlgl] Load mipmaps for cubemaps (#4429)

* [rlgl] Load cubemap mipmaps

* [rtextures] Only generate mipmaps that don't already exist

* [rtextures] ImageDraw(): Implement drawing to mipmaps

* [rtextures] Load cubemap mipmaps

examples/models/models_skybox.c

@@ -191,7 +191,7 @@ static TextureCubemap GenTextureCubemap(Shader shader, Texture2D panorama, int s
     // STEP 1: Setup framebuffer
     //------------------------------------------------------------------------------------------
     unsigned int rbo = rlLoadTextureDepth(size, size, true);
-    cubemap.id = rlLoadTextureCubemap(0, size, format);
+    cubemap.id = rlLoadTextureCubemap(0, size, format, 1);
 
     unsigned int fbo = rlLoadFramebuffer();
     rlFramebufferAttach(fbo, rbo, RL_ATTACHMENT_DEPTH, RL_ATTACHMENT_RENDERBUFFER, 0);

src/rlgl.h

@@ -749,7 +749,7 @@ RLAPI void rlDrawVertexArrayElementsInstanced(int offset, int count, const void
 // Textures management
 RLAPI unsigned int rlLoadTexture(const void *data, int width, int height, int format, int mipmapCount); // Load texture data
 RLAPI unsigned int rlLoadTextureDepth(int width, int height, bool useRenderBuffer); // Load depth texture/renderbuffer (to be attached to fbo)
-RLAPI unsigned int rlLoadTextureCubemap(const void *data, int size, int format); // Load texture cubemap data
+RLAPI unsigned int rlLoadTextureCubemap(const void *data, int size, int format, int mipmapCount); // Load texture cubemap data
 RLAPI void rlUpdateTexture(unsigned int id, int offsetX, int offsetY, int width, int height, int format, const void *data); // Update texture with new data on GPU
 RLAPI void rlGetGlTextureFormats(int format, unsigned int *glInternalFormat, unsigned int *glFormat, unsigned int *glType); // Get OpenGL internal formats
 RLAPI const char *rlGetPixelFormatName(unsigned int format);              // Get name string for pixel format
@@ -3386,11 +3386,17 @@ unsigned int rlLoadTextureDepth(int width, int height, bool useRenderBuffer)
 // Load texture cubemap
 // NOTE: Cubemap data is expected to be 6 images in a single data array (one after the other),
 // expected the following convention: +X, -X, +Y, -Y, +Z, -Z
-unsigned int rlLoadTextureCubemap(const void *data, int size, int format)
+unsigned int rlLoadTextureCubemap(const void *data, int size, int format, int mipmapCount)
 {
     unsigned int id = 0;
 
 #if defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES2)
+    int mipSize = size;
+
+    // NOTE: Added pointer math separately from function to avoid UBSAN complaining
+    unsigned char *dataPtr = NULL;
+    if (data != NULL) dataPtr = (unsigned char *)data;
+
     unsigned int dataSize = rlGetPixelDataSize(size, size, format);
 
     glGenTextures(1, &id);
@@ -3401,9 +3407,12 @@ unsigned int rlLoadTextureCubemap(const void *data, int size, int format)
 
     if (glInternalFormat != 0)
     {
-        // Load cubemap faces
-        for (unsigned int i = 0; i < 6; i++)
+        // Load cubemap faces/mipmaps
+        for (unsigned int i = 0; i < 6 * mipmapCount; i++)
         {
+            int mipmapLevel = i / 6;
+            int face = i % 6;
+
             if (data == NULL)
             {
                 if (format < RL_PIXELFORMAT_COMPRESSED_DXT1_RGB)
@@ -3411,14 +3420,14 @@ unsigned int rlLoadTextureCubemap(const void *data, int size, int format)
                     if ((format == RL_PIXELFORMAT_UNCOMPRESSED_R32) || (format == RL_PIXELFORMAT_UNCOMPRESSED_R32G32B32A32)
                             || (format == RL_PIXELFORMAT_UNCOMPRESSED_R16) || (format == RL_PIXELFORMAT_UNCOMPRESSED_R16G16B16A16))
                         TRACELOG(RL_LOG_WARNING, "TEXTURES: Cubemap requested format not supported");
-                    else glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, glInternalFormat, size, size, 0, glFormat, glType, NULL);
+                    else glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, mipmapLevel, glInternalFormat, mipSize, mipSize, 0, glFormat, glType, NULL);
                 }
                 else TRACELOG(RL_LOG_WARNING, "TEXTURES: Empty cubemap creation does not support compressed format");
             }
             else
             {
-                if (format < RL_PIXELFORMAT_COMPRESSED_DXT1_RGB) glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, glInternalFormat, size, size, 0, glFormat, glType, (unsigned char *)data + i*dataSize);
-                else glCompressedTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, glInternalFormat, size, size, 0, dataSize, (unsigned char *)data + i*dataSize);
+                if (format < RL_PIXELFORMAT_COMPRESSED_DXT1_RGB) glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, mipmapLevel, glInternalFormat, mipSize, mipSize, 0, glFormat, glType, (unsigned char *)dataPtr + face*dataSize);
+                else glCompressedTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, mipmapLevel, glInternalFormat, mipSize, mipSize, 0, dataSize, (unsigned char *)dataPtr + face*dataSize);
             }
 
 #if defined(GRAPHICS_API_OPENGL_33)
@@ -3437,11 +3446,25 @@ unsigned int rlLoadTextureCubemap(const void *data, int size, int format)
                 glTexParameteriv(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_SWIZZLE_RGBA, swizzleMask);
             }
 #endif
+            if (face == 5) {
+                mipSize /= 2;
+                if (data != NULL)
+                    dataPtr += dataSize * 6;         // Increment data pointer to next mipmap
+
+                // Security check for NPOT textures
+                if (mipSize < 1) mipSize = 1;
+
+                dataSize = rlGetPixelDataSize(mipSize, mipSize, format);
+            }
         }
     }
 
     // Set cubemap texture sampling parameters
-    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    if (mipmapCount > 1) {
+        glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+    } else {
+        glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    }
     glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
     glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

src/rtextures.c

@@ -2390,22 +2390,16 @@ void ImageMipmaps(Image *image)
         else TRACELOG(LOG_WARNING, "IMAGE: Mipmaps required memory could not be allocated");
 
         // Pointer to allocated memory point where store next mipmap level data
-        unsigned char *nextmip = (unsigned char *)image->data + GetPixelDataSize(image->width, image->height, image->format);
+        unsigned char *nextmip = image->data;
 
-        mipWidth = image->width/2;
-        mipHeight = image->height/2;
+        mipWidth = image->width;
+        mipHeight = image->height;
         mipSize = GetPixelDataSize(mipWidth, mipHeight, image->format);
         Image imCopy = ImageCopy(*image);
 
         for (int i = 1; i < mipCount; i++)
         {
-            TRACELOGD("IMAGE: Generating mipmap level: %i (%i x %i) - size: %i - offset: 0x%x", i, mipWidth, mipHeight, mipSize, nextmip);
-
-            ImageResize(&imCopy, mipWidth, mipHeight);  // Uses internally Mitchell cubic downscale filter
-
-            memcpy(nextmip, imCopy.data, mipSize);
             nextmip += mipSize;
-            image->mipmaps++;
 
             mipWidth /= 2;
             mipHeight /= 2;
@@ -2415,9 +2409,20 @@ void ImageMipmaps(Image *image)
             if (mipHeight < 1) mipHeight = 1;
 
             mipSize = GetPixelDataSize(mipWidth, mipHeight, image->format);
+
+            if (i < image->mipmaps)
+                continue;
+
+            TRACELOGD("IMAGE: Generating mipmap level: %i (%i x %i) - size: %i - offset: 0x%x", i, mipWidth, mipHeight, mipSize, nextmip);
+
+            ImageResize(&imCopy, mipWidth, mipHeight);  // Uses internally Mitchell cubic downscale filter
+
+            memcpy(nextmip, imCopy.data, mipSize);
         }
 
         UnloadImage(imCopy);
+
+        image->mipmaps = mipCount;
     }
     else TRACELOG(LOG_WARNING, "IMAGE: Mipmaps already available");
 }
@@ -3906,7 +3911,6 @@ void ImageDraw(Image *dst, Image src, Rectangle srcRec, Rectangle dstRec, Color
     if ((dst->data == NULL) || (dst->width == 0) || (dst->height == 0) ||
         (src.data == NULL) || (src.width == 0) || (src.height == 0)) return;
 
-    if (dst->mipmaps > 1) TRACELOG(LOG_WARNING, "Image drawing only applied to base mipmap level");
     if (dst->format >= PIXELFORMAT_COMPRESSED_DXT1_RGB) TRACELOG(LOG_WARNING, "Image drawing not supported for compressed formats");
     else
     {
@@ -4019,6 +4023,34 @@ void ImageDraw(Image *dst, Image src, Rectangle srcRec, Rectangle dstRec, Color
         }
 
         if (useSrcMod) UnloadImage(srcMod);     // Unload source modified image
+
+        if (dst->mipmaps > 1 && src.mipmaps > 1) {
+            Image mipmapDst = *dst;
+            mipmapDst.data = (char *) mipmapDst.data + GetPixelDataSize(mipmapDst.width, mipmapDst.height, mipmapDst.format);
+            mipmapDst.width /= 2;
+            mipmapDst.height /= 2;
+            mipmapDst.mipmaps--;
+
+            Image mipmapSrc = src;
+            mipmapSrc.data = (char *) mipmapSrc.data + GetPixelDataSize(mipmapSrc.width, mipmapSrc.height, mipmapSrc.format);
+            mipmapSrc.width /= 2;
+            mipmapSrc.height /= 2;
+            mipmapSrc.mipmaps--;
+
+            Rectangle mipmapSrcRec = srcRec;
+            mipmapSrcRec.width /= 2;
+            mipmapSrcRec.height /= 2;
+            mipmapSrcRec.x /= 2;
+            mipmapSrcRec.y /= 2;
+
+            Rectangle mipmapDstRec = dstRec;
+            mipmapDstRec.width /= 2;
+            mipmapDstRec.height /= 2;
+            mipmapDstRec.x /= 2;
+            mipmapDstRec.y /= 2;
+
+            ImageDraw(&mipmapDst, mipmapSrc, mipmapSrcRec, mipmapDstRec, tint);
+        }
     }
 }
 
@@ -4162,6 +4194,9 @@ TextureCubemap LoadTextureCubemap(Image image, int layout)
             faces = GenImageColor(size, size*6, MAGENTA);
             ImageFormat(&faces, image.format);
 
+            ImageMipmaps(&image);
+            ImageMipmaps(&faces);
+
             // NOTE: Image formatting does not work with compressed textures
 
             for (int i = 0; i < 6; i++) ImageDraw(&faces, image, faceRecs[i], (Rectangle){ 0, (float)size*i, (float)size, (float)size }, WHITE);
@@ -4169,7 +4204,7 @@ TextureCubemap LoadTextureCubemap(Image image, int layout)
 
         // NOTE: Cubemap data is expected to be provided as 6 images in a single data array,
         // one after the other (that's a vertical image), following convention: +X, -X, +Y, -Y, +Z, -Z
-        cubemap.id = rlLoadTextureCubemap(faces.data, size, faces.format);
+        cubemap.id = rlLoadTextureCubemap(faces.data, size, faces.format, faces.mipmaps);
 
         if (cubemap.id != 0)
         {