Handle PVRTC1 minimum 2 block requirement. Fixes issue KhronosGroup#390…

…. (KhronosGroup#398)
KaperD · Apr 15, 2021 · 46e1a2f · 46e1a2f
1 parent 6c01c3b
commit 46e1a2f
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Showing 5 changed files with 59 additions and 18 deletions.
diff --git a/lib/formatsize.h b/lib/formatsize.h
@@ -41,6 +41,8 @@ typedef struct ktxFormatSize {
     unsigned int        blockWidth;         // in texels
     unsigned int        blockHeight;        // in texels
     unsigned int        blockDepth;         // in texels
+    unsigned int        minBlocksX;         // Minimum required number of blocks
+    unsigned int        minBlocksY;
 } ktxFormatSize;
 
 #ifdef __cplusplus

diff --git a/lib/gl_format.h b/lib/gl_format.h
@@ -1,4 +1,4 @@
-/*
+/*
 ================================================================================================
 
 Description	:	OpenGL formats/types and properties.
@@ -1625,6 +1625,7 @@ static inline unsigned int glGetTypeSizeFromType(GLenum type)
 
 static inline void glGetFormatSize( const GLenum internalFormat, ktxFormatSize * pFormatSize )
 {
+    pFormatSize->minBlocksX = pFormatSize->minBlocksY = 1;
 	switch ( internalFormat )
 	{
 		//
@@ -2007,27 +2008,31 @@ static inline void glGetFormatSize( const GLenum internalFormat, ktxFormatSize *
 		//
 		// PVRTC
 		//
-		case GL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG:				// 3-component PVRTC, 16x8 blocks, unsigned normalized
-		case GL_COMPRESSED_SRGB_PVRTC_2BPPV1_EXT:				// 3-component PVRTC, 16x8 blocks, sRGB
-		case GL_COMPRESSED_RGBA_PVRTC_2BPPV1_IMG:				// 4-component PVRTC, 16x8 blocks, unsigned normalized
-		case GL_COMPRESSED_SRGB_ALPHA_PVRTC_2BPPV1_EXT:			// 4-component PVRTC, 16x8 blocks, sRGB
+		case GL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG:				// 3-component PVRTC, 8x4 blocks, unsigned normalized
+		case GL_COMPRESSED_SRGB_PVRTC_2BPPV1_EXT:				// 3-component PVRTC, 8x4 blocks, sRGB
+		case GL_COMPRESSED_RGBA_PVRTC_2BPPV1_IMG:				// 4-component PVRTC, 8x4 blocks, unsigned normalized
+		case GL_COMPRESSED_SRGB_ALPHA_PVRTC_2BPPV1_EXT:			// 4-component PVRTC, 8x4 blocks, sRGB
 			pFormatSize->flags = KTX_FORMAT_SIZE_COMPRESSED_BIT;
 			pFormatSize->paletteSizeInBits = 0;
 			pFormatSize->blockSizeInBits = 64;
-			pFormatSize->blockWidth = 16;
-			pFormatSize->blockHeight = 8;
+			pFormatSize->blockWidth = 8;
+			pFormatSize->blockHeight = 4;
 			pFormatSize->blockDepth = 1;
+            pFormatSize->minBlocksX = 2;
+            pFormatSize->minBlocksY = 2;
 			break;
-		case GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG:				// 3-component PVRTC, 8x8 blocks, unsigned normalized
-		case GL_COMPRESSED_SRGB_PVRTC_4BPPV1_EXT:				// 3-component PVRTC, 8x8 blocks, sRGB
-		case GL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG:				// 4-component PVRTC, 8x8 blocks, unsigned normalized
-		case GL_COMPRESSED_SRGB_ALPHA_PVRTC_4BPPV1_EXT:			// 4-component PVRTC, 8x8 blocks, sRGB
+		case GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG:				// 3-component PVRTC, 4x4 blocks, unsigned normalized
+		case GL_COMPRESSED_SRGB_PVRTC_4BPPV1_EXT:				// 3-component PVRTC, 4x4 blocks, sRGB
+		case GL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG:				// 4-component PVRTC, 4x4 blocks, unsigned normalized
+		case GL_COMPRESSED_SRGB_ALPHA_PVRTC_4BPPV1_EXT:			// 4-component PVRTC, 4x4 blocks, sRGB
 			pFormatSize->flags = KTX_FORMAT_SIZE_COMPRESSED_BIT;
 			pFormatSize->paletteSizeInBits = 0;
 			pFormatSize->blockSizeInBits = 64;
-			pFormatSize->blockWidth = 8;
-			pFormatSize->blockHeight = 8;
+			pFormatSize->blockWidth = 4;
+			pFormatSize->blockHeight = 4;
 			pFormatSize->blockDepth = 1;
+            pFormatSize->minBlocksX = 2;
+            pFormatSize->minBlocksY = 2;
 			break;
 		case GL_COMPRESSED_RGBA_PVRTC_2BPPV2_IMG:				// 4-component PVRTC, 8x4 blocks, unsigned normalized
 		case GL_COMPRESSED_SRGB_ALPHA_PVRTC_2BPPV2_IMG:			// 4-component PVRTC, 8x4 blocks, sRGB

diff --git a/lib/texture.c b/lib/texture.c
@@ -565,8 +565,8 @@ ktxTexture_calcImageSize(ktxTexture* This, ktx_uint32_t level,
         = (uint32_t)ceilf(levelWidth / prtctd->_formatSize.blockWidth);
     blockCount.y
         = (uint32_t)ceilf(levelHeight / prtctd->_formatSize.blockHeight);
-    blockCount.x = MAX(1, blockCount.x);
-    blockCount.y = MAX(1, blockCount.y);
+    blockCount.x = MAX(prtctd->_formatSize.minBlocksX, blockCount.x);
+    blockCount.y = MAX(prtctd->_formatSize.minBlocksX, blockCount.y);
 
     blockSizeInBytes = prtctd->_formatSize.blockSizeInBits / 8;
 

diff --git a/lib/texture2.c b/lib/texture2.c
@@ -235,9 +235,13 @@ ktxFormatSize_initFromDfd(ktxFormatSize* This, ktx_uint32_t* pDfd)
     This->blockSizeInBits = KHR_DFDVAL(pBdb, BYTESPLANE0) * 8;
     This->paletteSizeInBits = 0; // No paletted formats in ktx v2.
     This->flags = 0;
+    This->minBlocksX = This->minBlocksY = 1;
     if (KHR_DFDVAL(pBdb, MODEL) >= KHR_DF_MODEL_DXT1A) {
         // A block compressed format. Entire block is a single sample.
         This->flags |= KTX_FORMAT_SIZE_COMPRESSED_BIT;
+        if (KHR_DFDVAL(pBdb, MODEL) == KHR_DF_MODEL_PVRTC) {
+            This->minBlocksX = This->minBlocksY = 2;
+        }
     } else {
         // An uncompressed format.
 
@@ -2001,7 +2005,7 @@ ktxTexture2_IterateLoadLevelFaces(ktxTexture2* This, PFNKTXITERCB iterCb,
         // With the exception of non-array cubemaps the entire level
         // is passed at once because that is how OpenGL and Vulkan need them.
         // Vulkan could take all the faces at once too but we iterate
-        // them separately or OpenGL.
+        // them separately for OpenGL.
         if (This->isCubemap && !This->isArray) {
             ktx_uint8_t* pFace = pData;
             struct blockCount {
@@ -2013,8 +2017,8 @@ ktxTexture2_IterateLoadLevelFaces(ktxTexture2* This, PFNKTXITERCB iterCb,
               = (uint32_t)ceilf((float)width / prtctd->_formatSize.blockWidth);
             blockCount.y
               = (uint32_t)ceilf((float)height / prtctd->_formatSize.blockHeight);
-            blockCount.x = MAX(1, blockCount.x);
-            blockCount.y = MAX(1, blockCount.y);
+            blockCount.x = MAX(prtctd->_formatSize.minBlocksX, blockCount.x);
+            blockCount.y = MAX(prtctd->_formatSize.minBlocksX, blockCount.y);
             faceSize = blockCount.x * blockCount.y
                        * prtctd->_formatSize.blockSizeInBits / 8;
 

diff --git a/lib/vk_format.h b/lib/vk_format.h
@@ -825,6 +825,7 @@ static inline VkFormat vkGetFormatFromOpenGLInternalFormat( const GLenum interna
 
 static inline void vkGetFormatSize( const VkFormat format, ktxFormatSize * pFormatSize )
 {
+    pFormatSize->minBlocksX = pFormatSize->minBlocksY = 1;
 	switch ( format )
 	{
 		case VK_FORMAT_R4G4_UNORM_PACK8:
@@ -1207,8 +1208,37 @@ static inline void vkGetFormatSize( const VkFormat format, ktxFormatSize * pForm
 			pFormatSize->blockHeight = 4;
 			pFormatSize->blockDepth = 1;
 			break;
+		case VK_FORMAT_PVRTC1_2BPP_SRGB_BLOCK_IMG:
+		case VK_FORMAT_PVRTC1_2BPP_UNORM_BLOCK_IMG:
+			pFormatSize->flags = KTX_FORMAT_SIZE_COMPRESSED_BIT;
+			pFormatSize->paletteSizeInBits = 0;
+			pFormatSize->blockSizeInBits = 8 * 8;
+			pFormatSize->blockWidth = 8;
+			pFormatSize->blockHeight = 4;
+			pFormatSize->blockDepth = 1;
+            pFormatSize->minBlocksX = 2;
+            pFormatSize->minBlocksY = 2;
+            break;
+        case VK_FORMAT_PVRTC2_2BPP_SRGB_BLOCK_IMG:
+        case VK_FORMAT_PVRTC2_2BPP_UNORM_BLOCK_IMG:
+			pFormatSize->flags = KTX_FORMAT_SIZE_COMPRESSED_BIT;
+			pFormatSize->paletteSizeInBits = 0;
+			pFormatSize->blockSizeInBits = 8 * 8;
+			pFormatSize->blockWidth = 8;
+			pFormatSize->blockHeight = 4;
+			pFormatSize->blockDepth = 1;
+			break;
 		case VK_FORMAT_PVRTC1_4BPP_SRGB_BLOCK_IMG:
 		case VK_FORMAT_PVRTC1_4BPP_UNORM_BLOCK_IMG:
+			pFormatSize->flags = KTX_FORMAT_SIZE_COMPRESSED_BIT;
+			pFormatSize->paletteSizeInBits = 0;
+			pFormatSize->blockSizeInBits = 8 * 8;
+			pFormatSize->blockWidth = 4;
+			pFormatSize->blockHeight = 4;
+			pFormatSize->blockDepth = 1;
+            pFormatSize->minBlocksX = 2;
+            pFormatSize->minBlocksY = 2;
+            break;
         case VK_FORMAT_PVRTC2_4BPP_SRGB_BLOCK_IMG:
         case VK_FORMAT_PVRTC2_4BPP_UNORM_BLOCK_IMG:
 			pFormatSize->flags = KTX_FORMAT_SIZE_COMPRESSED_BIT;