gl-renderer: Add coefficients and range support to internal shader

Add matrix-coefficients and range tracking to more gl-renderer structures
and get the relevant values from the color-representation implementation
instead of hard-coding them in the shader.

Signed-off-by: Robert Mader <robert.mader@collabora.com>

libweston/renderer-gl/fragment.glsl

@@ -95,29 +95,16 @@ compile_const bool c_need_color_pipeline =
 compile_const bool c_need_straight_alpha =
 	c_need_color_pipeline || c_color_effect != SHADER_COLOR_EFFECT_NONE;
 
+uniform HIGHPRECISION mat3 yuv_coefficients;
+uniform HIGHPRECISION vec3 yuv_offsets;
+
 vec4
 yuva2rgba(vec4 yuva)
 {
 	vec4 color_out;
-	float Y, su, sv;
-
-	/* ITU-R BT.601 & BT.709 quantization (limited range) */
-
-	Y = 255.0/219.0 * (yuva.x - 16.0/255.0);
-
-	/* Remove offset 128/255, but the 255/224 multiplier comes later */
-	su = yuva.y - 128.0/255.0;
-	sv = yuva.z - 128.0/255.0;
-
-	/*
-	 * ITU-R BT.709 encoding coefficients (inverse), with the
-	 * 255/224 limited range multiplier already included in the
-	 * factors for su (Cb) and sv (Cr).
-	 */
-	color_out.r = Y                   + 1.79274107 * sv;
-	color_out.g = Y - 0.21324861 * su - 0.53290933 * sv;
-	color_out.b = Y + 2.11240179 * su;
 
+	color_out.rgb = yuv_coefficients * (yuva.xyz - yuv_offsets);
+	color_out.rgb *= yuva.w;
 	color_out.a = yuva.w;
 
 	return color_out;

libweston/renderer-gl/gl-renderer-internal.h

@@ -390,6 +390,9 @@ struct gl_shader_config {
 	union gl_shader_config_color_curve color_pre_curve;
 	union gl_shader_config_color_mapping color_mapping;
 	union gl_shader_config_color_curve color_post_curve;
+
+	enum weston_color_matrix_coef yuv_coefficients;
+	enum weston_color_quant_range yuv_range;
 };
 
 struct gl_renderer {

libweston/renderer-gl/gl-renderer.c

@@ -49,6 +49,7 @@
 #include "timeline.h"
 
 #include "color.h"
+#include "color-representation.h"
 #include "gl-renderer.h"
 #include "gl-renderer-internal.h"
 #include "vertex-clipping.h"
@@ -63,6 +64,7 @@
 #include "shared/platform.h"
 #include "shared/string-helpers.h"
 #include "shared/timespec-util.h"
+#include "shared/weston-assert.h"
 #include "shared/weston-drm-fourcc.h"
 #include "shared/weston-egl-ext.h"
 #include "shared/xalloc.h"
@@ -1464,6 +1466,7 @@ prepare_textured_draw(struct gl_shader_config *sconf,
 	struct gl_buffer_state *gb = gs->buffer;
 	struct gl_output_state *go = get_output_state(pnode->output);
 	struct weston_buffer *buffer = gs->buffer_ref.buffer;
+	struct weston_color_representation color_rep;
 	GLint filter;
 	int i;
 
@@ -1508,6 +1511,12 @@ prepare_textured_draw(struct gl_shader_config *sconf,
 		return false;
 	}
 
+	color_rep =
+		weston_fill_color_representation(&pnode->surface->color_representation,
+						 buffer->pixel_format);
+	sconf->yuv_coefficients = color_rep.matrix_coefficients;
+	sconf->yuv_range = color_rep.quant_range;
+
 	return true;
 }
 

libweston/renderer-gl/gl-shaders.c

@@ -34,6 +34,7 @@
 #include <string.h>
 #include <assert.h>
 
+#include <libweston/color-representation.h>
 #include <libweston/libweston.h>
 #include <libweston/weston-log.h>
 
@@ -99,6 +100,8 @@ struct gl_shader {
 	union gl_shader_color_curve_uniforms color_pre_curve;
 	union gl_shader_color_mapping_uniforms color_mapping;
 	union gl_shader_color_curve_uniforms color_post_curve;
+	GLint yuv_offsets_uniform;
+	GLint yuv_coefficients_uniform;
 };
 
 static const char *
@@ -503,6 +506,12 @@ gl_shader_create(struct gl_renderer *gr,
 	case SHADER_COLOR_MAPPING_IDENTITY:
 		break;
 	}
+
+	shader->yuv_coefficients_uniform =
+		glGetUniformLocation(shader->program, "yuv_coefficients");
+	shader->yuv_offsets_uniform = glGetUniformLocation(shader->program,
+							   "yuv_offsets");
+
 	free(conf);
 
 	wl_list_insert(&gr->shader_list, &shader->link);
@@ -752,6 +761,28 @@ gl_shader_load_config_mapping(struct weston_compositor *compositor,
 	weston_assert_not_reached(compositor, "unknown enum gl_shader_color_mapping value");
 }
 
+static void
+gl_shader_load_config_representation(struct weston_compositor *compositor,
+				     struct gl_shader *shader,
+				     const struct gl_shader_config *sconf)
+{
+	struct weston_color_representation_matrix cr_matrix;
+
+	if (sconf->yuv_coefficients == WESTON_COLOR_MATRIX_COEF_UNSET ||
+	    sconf->yuv_coefficients == WESTON_COLOR_MATRIX_COEF_IDENTITY) {
+		assert(shader->yuv_coefficients_uniform == -1);
+		assert(shader->yuv_offsets_uniform == -1);
+		return;
+	}
+
+	weston_get_color_representation_matrix(compositor,
+		sconf->yuv_coefficients, sconf->yuv_range, &cr_matrix);
+
+	glUniformMatrix3fv(shader->yuv_coefficients_uniform, 1, GL_FALSE,
+			   cr_matrix.matrix.colmaj);
+	glUniform3fv(shader->yuv_offsets_uniform, 1, cr_matrix.offset.el);
+}
+
 bool
 gl_shader_texture_variant_can_be_premult(enum gl_shader_texture_variant v)
 {
@@ -859,6 +890,8 @@ gl_shader_load_config(struct gl_renderer *gr,
 				    &sconf->color_post_curve, &shader->color_post_curve,
 				    TEX_UNIT_COLOR_POST_CURVE);
 
+	gl_shader_load_config_representation(gr->compositor, shader, sconf);
+
 	if (sconf->req.wireframe)
 		glUniform1i(shader->tex_uniform_wireframe, TEX_UNIT_WIREFRAME);