OpenGL: Support FORMAT_{ETC2,DXT5}_RA_AS_RG

This commit adds support for FORMAT_EXT2_RA_AS_RG and
FORMAT_DXT5_RA_AS_RG with OpenGL, fixing VRAM compression with the
normal map option enabled.

1 files changed, 49 insertions, 6 deletions

diff --git a/drivers/gles3/storage/texture_storage.cpp b/drivers/gles3/storage/texture_storage.cpp
index 2f0a253e46..489c328f64 100644
--- a/drivers/gles3/storage/texture_storage.cpp
+++ b/drivers/gles3/storage/texture_storage.cpp
@@ -300,6 +300,7 @@ Ref<Image> TextureStorage::_get_gl_image_and_format(const Ref<Image> &p_image, I
 	r_real_format = p_format;
 
 	bool need_decompress = false;
+	bool decompress_ra_to_rg = false;
 
 	switch (p_format) {
 		case Image::FORMAT_L8: {
@@ -565,6 +566,28 @@ Ref<Image> TextureStorage::_get_gl_image_and_format(const Ref<Image> &p_image, I
 				need_decompress = true;
 			}
 		} break;
+		case Image::FORMAT_ETC2_RA_AS_RG: {
+			if (config->etc2_supported) {
+				r_gl_internal_format = _EXT_COMPRESSED_RGBA8_ETC2_EAC;
+				r_gl_format = GL_RGBA;
+				r_gl_type = GL_UNSIGNED_BYTE;
+				r_compressed = true;
+			} else {
+				need_decompress = true;
+			}
+			decompress_ra_to_rg = true;
+		} break;
+		case Image::FORMAT_DXT5_RA_AS_RG: {
+			if (config->s3tc_supported) {
+				r_gl_internal_format = _EXT_COMPRESSED_RGBA_S3TC_DXT5_EXT;
+				r_gl_format = GL_RGBA;
+				r_gl_type = GL_UNSIGNED_BYTE;
+				r_compressed = true;
+			} else {
+				need_decompress = true;
+			}
+			decompress_ra_to_rg = true;
+		} break;
 		default: {
 			ERR_FAIL_V_MSG(Ref<Image>(), "Image Format: " + itos(p_format) + " is not supported by the OpenGL3 Renderer");
 		}
@@ -575,7 +598,18 @@ Ref<Image> TextureStorage::_get_gl_image_and_format(const Ref<Image> &p_image, I
 			image = image->duplicate();
 			image->decompress();
 			ERR_FAIL_COND_V(image->is_compressed(), image);
+			if (decompress_ra_to_rg) {
+				image->convert_ra_rgba8_to_rg();
+				image->convert(Image::FORMAT_RG8);
+			}
 			switch (image->get_format()) {
+				case Image::FORMAT_RG8: {
+					r_gl_format = GL_RG;
+					r_gl_internal_format = GL_RG8;
+					r_gl_type = GL_UNSIGNED_BYTE;
+					r_real_format = Image::FORMAT_RG8;
+					r_compressed = false;
+				} break;
 				case Image::FORMAT_RGB8: {
 					r_gl_format = GL_RGB;
 					r_gl_internal_format = GL_RGB;
@@ -597,7 +631,6 @@ Ref<Image> TextureStorage::_get_gl_image_and_format(const Ref<Image> &p_image, I
 					r_gl_type = GL_UNSIGNED_BYTE;
 					r_real_format = Image::FORMAT_RGBA8;
 					r_compressed = false;
-
 				} break;
 			}
 		}
@@ -1104,15 +1137,13 @@ void TextureStorage::texture_set_data(RID p_texture, const Ref<Image> &p_image,
 	texture->gl_set_filter(RS::CANVAS_ITEM_TEXTURE_FILTER_NEAREST);
 	texture->gl_set_repeat(RS::CANVAS_ITEM_TEXTURE_REPEAT_ENABLED);
 
-	//set swizle for older format compatibility
-#ifdef GLES_OVER_GL
 	switch (texture->format) {
+#ifdef GLES_OVER_GL
 		case Image::FORMAT_L8: {
 			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_R, GL_RED);
 			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_G, GL_RED);
 			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_B, GL_RED);
 			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_A, GL_ONE);
-
 		} break;
 		case Image::FORMAT_LA8: {
 			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_R, GL_RED);
@@ -1120,15 +1151,27 @@ void TextureStorage::texture_set_data(RID p_texture, const Ref<Image> &p_image,
 			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_B, GL_RED);
 			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_A, GL_GREEN);
 		} break;
+#endif
+		case Image::FORMAT_ETC2_RA_AS_RG:
+		case Image::FORMAT_DXT5_RA_AS_RG: {
+			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_R, GL_RED);
+			if (texture->format == real_format) {
+				// Swizzle RA from compressed texture into RG
+				glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_G, GL_ALPHA);
+			} else {
+				// Converted textures are already in RG, leave as-is
+				glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_G, GL_GREEN);
+			}
+			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_B, GL_ZERO);
+			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_A, GL_ONE);
+		} break;
 		default: {
 			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_R, GL_RED);
 			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_G, GL_GREEN);
 			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_B, GL_BLUE);
 			glTexParameteri(texture->target, GL_TEXTURE_SWIZZLE_A, GL_ALPHA);
-
 		} break;
 	}
-#endif
 
 	int mipmaps = img->has_mipmaps() ? img->get_mipmap_count() + 1 : 1;