wip: render/gles2: add support for 3D LUT transforms

include/render/gles2.h

@@ -64,6 +64,7 @@ struct wlr_gles2_renderer {
 		PFNGLPUSHDEBUGGROUPKHRPROC glPushDebugGroupKHR;
 		PFNGLEGLIMAGETARGETRENDERBUFFERSTORAGEOESPROC glEGLImageTargetRenderbufferStorageOES;
 		PFNGLGETGRAPHICSRESETSTATUSKHRPROC glGetGraphicsResetStatusKHR;
+		PFNGLTEXIMAGE3DOESPROC glTexImage3DOES;
 	} procs;
 
 	struct {
@@ -121,6 +122,16 @@ enum wlr_gles2_shader_source {
 	WLR_GLES2_SHADER_SOURCE_TEXTURE_EXTERNAL = 4,
 };
 
+enum wlr_gles2_shader_color_transform {
+	WLR_GLES2_SHADER_COLOR_TRANSFORM_IDENTITY = 0,
+	WLR_GLES2_SHADER_COLOR_TRANSFORM_LUT_3D = 1,
+};
+
+struct wlr_gles2_shader_params {
+	enum wlr_gles2_shader_source source;
+	enum wlr_gles2_shader_color_transform color_transform;
+};
+
 bool is_gles2_pixel_format_supported(const struct wlr_gles2_renderer *renderer,
 	const struct wlr_gles2_pixel_format *format);
 const struct wlr_gles2_pixel_format *get_gles2_format_from_drm(uint32_t fmt);

render/gles2/renderer.c

@@ -627,10 +627,12 @@ static GLuint compile_shader(struct wlr_gles2_renderer *renderer,
 }
 
 static GLuint link_program(struct wlr_gles2_renderer *renderer,
-		enum wlr_gles2_shader_source source) {
+		const struct wlr_gles2_shader_params *params) {
 	static char frag_preamble[1024];
 	snprintf(frag_preamble, sizeof(frag_preamble),
-		"#define SOURCE %d\n", source);
+		"#define SOURCE %d\n"
+		"#define COLOR_TRANSFORM %d\n",
+		params->source, params->color_transform);
 
 	push_gles2_debug(renderer);
 
@@ -676,8 +678,8 @@ error:
 
 static bool link_tex_program(struct wlr_gles2_renderer *renderer,
 		struct wlr_gles2_tex_shader *shader,
-		enum wlr_gles2_shader_source source) {
+		const struct wlr_gles2_shader_params *params) {
-	shader->program = link_program(renderer, source);
+	shader->program = link_program(renderer, params);
 	if (!shader->program) {
 		return false;
 	}
@@ -829,6 +831,10 @@ struct wlr_renderer *wlr_gles2_renderer_create(struct wlr_egl *egl) {
 		}
 	}
 
+	if (check_gl_ext(exts_str, "GL_OES_texture_3D")) {
+		load_gl_proc(&renderer->procs.glTexImage3DOES, "glTexImage3DOES");
+	}
+
 	if (renderer->exts.KHR_debug) {
 		glEnable(GL_DEBUG_OUTPUT_KHR);
 		glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS_KHR);
@@ -843,9 +849,18 @@ struct wlr_renderer *wlr_gles2_renderer_create(struct wlr_egl *egl) {
 
 	push_gles2_debug(renderer);
 
+	enum wlr_gles2_shader_color_transform color_transform =
+		WLR_GLES2_SHADER_COLOR_TRANSFORM_IDENTITY;
+	if (renderer->procs.glTexImage3DOES != NULL) {
+		color_transform = WLR_GLES2_SHADER_COLOR_TRANSFORM_LUT_3D;
+	}
+
 	GLuint prog;
 	renderer->shaders.quad.program = prog =
-		link_program(renderer, WLR_GLES2_SHADER_SOURCE_SINGLE_COLOR);
+		link_program(renderer, &(struct wlr_gles2_shader_params){
+			.source = WLR_GLES2_SHADER_SOURCE_SINGLE_COLOR,
+			.color_transform = color_transform,
+		});
 	if (!renderer->shaders.quad.program) {
 		goto error;
 	}
@@ -854,16 +869,25 @@ struct wlr_renderer *wlr_gles2_renderer_create(struct wlr_egl *egl) {
 	renderer->shaders.quad.pos_attrib = glGetAttribLocation(prog, "pos");
 
 	if (!link_tex_program(renderer, &renderer->shaders.tex_rgba,
-			WLR_GLES2_SHADER_SOURCE_TEXTURE_RGBA)) {
+			&(struct wlr_gles2_shader_params){
+				.source = WLR_GLES2_SHADER_SOURCE_TEXTURE_RGBA,
+				.color_transform = color_transform,
+			})) {
 		goto error;
 	}
 	if (!link_tex_program(renderer, &renderer->shaders.tex_rgbx,
-			WLR_GLES2_SHADER_SOURCE_TEXTURE_RGBX)) {
+			&(struct wlr_gles2_shader_params){
+				.source = WLR_GLES2_SHADER_SOURCE_TEXTURE_RGBX,
+				.color_transform = color_transform,
+			})) {
 		goto error;
 	}
 	if (renderer->exts.OES_egl_image_external &&
 			!link_tex_program(renderer, &renderer->shaders.tex_ext,
-			WLR_GLES2_SHADER_SOURCE_TEXTURE_EXTERNAL)) {
+			&(struct wlr_gles2_shader_params){
+				.source = WLR_GLES2_SHADER_SOURCE_TEXTURE_EXTERNAL,
+				.color_transform = color_transform,
+			})) {
 		goto error;
 	}
 

render/gles2/shaders/common.frag

@@ -4,7 +4,11 @@
 #define SOURCE_TEXTURE_RGBX 3
 #define SOURCE_TEXTURE_EXTERNAL 4
 
-#if !defined(SOURCE)
+/* enum wlr_gles2_color_transform */
+#define COLOR_TRANSFORM_IDENTITY 0
+#define COLOR_TRANSFORM_LUT_3D 1
+
+#if !defined(SOURCE) || !defined(COLOR_TRANSFORM)
 #error "Missing shader preamble"
 #endif
 
@@ -12,6 +16,10 @@
 #extension GL_OES_EGL_image_external : require
 #endif
 
+#if COLOR_TRANSFORM == COLOR_TRANSFORM_3DLUT
+#extension GL_OES_texture_3D : require
+#endif
+
 precision mediump float;
 
 varying vec2 v_texcoord;
@@ -30,6 +38,12 @@ uniform float alpha;
 const float alpha = 1.0;
 #endif
 
+#if COLOR_TRANSFORM == COLOR_TRANSFORM_LUT_3D
+uniform mediump sampler3D lut_3d;
+uniform float lut_3d_offset;
+uniform float lut_3d_scale;
+#endif
+
 vec4 sample_texture() {
 #if SOURCE == SOURCE_TEXTURE_RGBA || SOURCE == SOURCE_TEXTURE_EXTERNAL
 	return texture2D(tex, v_texcoord);
@@ -40,6 +54,30 @@ vec4 sample_texture() {
 #endif
 }
 
-void main() {
+vec4 transform_color(vec4 color) {
-	gl_FragColor = sample_texture() * alpha;
+#if COLOR_TRANSFORM == COLOR_TRANSFORM_IDENTITY
+	return color;
+#elif COLOR_TRANSFORM == COLOR_TRANSFORM_LUT_3D
+	vec3 pos = lut_3d_offset + color * lut_3d_scale;
+	return texture3D(lut_3d, pos).rgb;
+#endif
+}
+
+void main() {
+	vec4 color = sample_texture() * alpha;
+
+#if COLOR_TRANSFORM != COLOR_TRANSFORM_IDENTITY
+	// Convert from pre-multiplied alpha to straight alpha
+	if (color.a == 0.0)
+		color.rgb = vec3(0.0, 0.0, 0.0);
+	else
+		color.rgb /= color.a;
+
+	color = transform_color(color);
+
+	// Convert from straight alpha to pre-multiplied alpha
+	color.rgb *= color.a;
+#endif
+
+	gl_FragColor = color;
 }