Function FormatCompressedTexture

Chapter_14/src/Textures.cpp:147–184

* Copy a compressed BC7 texture into our format, aligned for GPU use. */

	 * Copy a compressed BC7 texture into our format, aligned for GPU use.
	 */
	bool FormatCompressedTexture(ScratchImage& src, Texture& dst)
	{
		// Get the texture's metadata
		const TexMetadata metadata = src.GetMetadata();

		// Check if the texture's format is supported
		if (metadata.format != DXGI_FORMAT_BC7_UNORM && metadata.format != DXGI_FORMAT_BC7_UNORM_SRGB && metadata.format != DXGI_FORMAT_BC7_TYPELESS)
		{
			std::string msg = "Error: unsupported compressed texture format for: \'" + dst.name + "\' \'" + dst.filepath + "\'\n. Compressed textures must be in BC7 format";
			MessageBox(NULL, std::wstring(msg.begin(), msg.end()).c_str(), L"Error", MB_OK);
			return false;
		}

		// Delete existing texels
		UnloadTexture(dst);

		// Copy each mip level to the texel array
		for (UINT mipIndex = 0; mipIndex < static_cast<UINT>(metadata.mipLevels); mipIndex++)
		{
			const Image* image = src.GetImage(mipIndex, 0, 0);

			TextureData mipData;
			mipData.width = image->width;
			mipData.height = image->height;
			mipData.texelBytes = image->slicePitch;
			mipData.stride = 4;
			mipData.rowPitch = image->rowPitch;

			// Copy texel data
			mipData.texels = new UINT8[mipData.texelBytes];
			memcpy(mipData.texels, image->pixels, image->slicePitch);

			dst.mips.push_back(mipData);
		}

		src.Release();
		return true;
	}

	/**
	 * Covert a R8G8B8A8_UNORM texture to BC7 format and generate mips.