gpu: Add a color shader

We don't want to use the pattern shader for simple colors, slow GPUs do
not like this at all.

gsk/gpu/gskgpucolorop.c

@@ -0,0 +1,77 @@
+#include "config.h"
+
+#include "gskgpucoloropprivate.h"
+
+#include "gskgpuframeprivate.h"
+#include "gskgpuprintprivate.h"
+#include "gskgpushaderopprivate.h"
+#include "gskrectprivate.h"
+
+#include "gpu/shaders/gskgpucolorinstance.h"
+
+typedef struct _GskGpuColorOp GskGpuColorOp;
+
+struct _GskGpuColorOp
+{
+  GskGpuShaderOp op;
+};
+
+static void
+gsk_gpu_color_op_finish (GskGpuOp *op)
+{
+}
+
+static void
+gsk_gpu_color_op_print (GskGpuOp    *op,
+                        GskGpuFrame *frame,
+                        GString     *string,
+                        guint        indent)
+{
+  GskGpuShaderOp *shader = (GskGpuShaderOp *) op;
+  GskGpuColorInstance *instance;
+
+  instance = (GskGpuColorInstance *) gsk_gpu_frame_get_vertex_data (frame, shader->vertex_offset);
+
+  gsk_gpu_print_op (string, indent, "color");
+  gsk_gpu_print_rect (string, instance->rect);
+  gsk_gpu_print_rgba (string, instance->color);
+  gsk_gpu_print_newline (string);
+}
+
+static const GskGpuShaderOpClass GSK_GPU_COLOR_OP_CLASS = {
+  {
+    GSK_GPU_OP_SIZE (GskGpuColorOp),
+    GSK_GPU_STAGE_SHADER,
+    gsk_gpu_color_op_finish,
+    gsk_gpu_color_op_print,
+#ifdef GDK_RENDERING_VULKAN
+    gsk_gpu_shader_op_vk_command,
+#endif
+    gsk_gpu_shader_op_gl_command
+  },
+  "gskgpucolor",
+  sizeof (GskGpuColorInstance),
+#ifdef GDK_RENDERING_VULKAN
+  &gsk_gpu_color_info,
+#endif
+  gsk_gpu_shader_op_no_images,
+  gsk_gpu_color_setup_vao
+};
+
+void
+gsk_gpu_color_op (GskGpuFrame            *frame,
+                  GskGpuShaderClip        clip,
+                  const graphene_rect_t  *rect,
+                  const graphene_point_t *offset,
+                  const GdkRGBA          *color)
+{
+  GskGpuColorInstance *instance;
+
+  gsk_gpu_shader_op_alloc (frame,
+                           &GSK_GPU_COLOR_OP_CLASS,
+                           clip,
+                           &instance);
+
+  gsk_gpu_rect_to_float (rect, offset, instance->rect);
+  gsk_gpu_rgba_to_float (color, instance->color);
+}

gsk/gpu/gskgpucoloropprivate.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include "gskgputypesprivate.h"
+
+#include <graphene.h>
+
+G_BEGIN_DECLS
+
+void                    gsk_gpu_color_op                                (GskGpuFrame                    *frame,
+                                                                         GskGpuShaderClip                clip,
+                                                                         const graphene_rect_t          *rect,
+                                                                         const graphene_point_t         *offset,
+                                                                         const GdkRGBA                  *color);
+
+
+G_END_DECLS
+

gsk/gpu/gskgpunodeprocessor.c

@@ -6,6 +6,7 @@
 #include "gskgpubluropprivate.h"
 #include "gskgpuclipprivate.h"
 #include "gskgpucolorizeopprivate.h"
+#include "gskgpucoloropprivate.h"
 #include "gskgpudeviceprivate.h"
 #include "gskgpuframeprivate.h"
 #include "gskgpuglobalsopprivate.h"
@@ -940,6 +941,17 @@ gsk_gpu_node_processor_add_transform_node (GskGpuNodeProcessor *self,
   self->pending_globals |= GSK_GPU_GLOBAL_MATRIX | GSK_GPU_GLOBAL_SCALE | GSK_GPU_GLOBAL_CLIP;
 }
 
+static void
+gsk_gpu_node_processor_add_color_node (GskGpuNodeProcessor *self,
+                                       GskRenderNode       *node)
+{
+  gsk_gpu_color_op (self->frame,
+                    gsk_gpu_clip_get_shader_clip (&self->clip, &self->offset, &node->bounds),
+                    &node->bounds,
+                    &self->offset,
+                    gsk_color_node_get_color (node));
+}
+
 static gboolean
 gsk_gpu_node_processor_create_color_pattern (GskGpuPatternWriter *self,
                                              GskRenderNode       *node)
@@ -1571,7 +1583,7 @@ static const struct
   },
   [GSK_COLOR_NODE] = {
     0,
-    gsk_gpu_node_processor_add_node_as_pattern,
+    gsk_gpu_node_processor_add_color_node,
     gsk_gpu_node_processor_create_color_pattern,
   },
   [GSK_LINEAR_GRADIENT_NODE] = {

gsk/gpu/shaders/gskgpucolor.glsl

@@ -0,0 +1,40 @@
+#include "common.glsl"
+
+PASS(0) vec2 _pos;
+PASS_FLAT(1) Rect _rect;
+PASS_FLAT(2) vec4 _color;
+
+
+
+#ifdef GSK_VERTEX_SHADER
+
+IN(0) vec4 in_rect;
+IN(1) vec4 in_color;
+
+void
+run (out vec2 pos)
+{
+  Rect r = rect_from_gsk (in_rect);
+  
+  pos = rect_get_position (r);
+
+  _pos = pos;
+  _rect = r;
+  _color = color_premultiply (in_color);
+}
+
+#endif
+
+
+
+#ifdef GSK_FRAGMENT_SHADER
+
+void
+run (out vec4 color,
+     out vec2 position)
+{
+  color = _color * rect_coverage (_rect, _pos);
+  position = _pos;
+}
+
+#endif

gsk/gpu/shaders/meson.build

@@ -14,6 +14,7 @@ gsk_private_gpu_include_shaders = files([
 gsk_private_gpu_shaders = files([
   'gskgpublur.glsl',
   'gskgpuborder.glsl',
+  'gskgpucolor.glsl',
   'gskgpucolorize.glsl',
   'gskgputexture.glsl',
   'gskgpuuber.glsl',

gsk/meson.build

@@ -78,6 +78,7 @@ gsk_private_sources = files([
   'gpu/gskgpubufferwriter.c',
   'gpu/gskgpuclip.c',
   'gpu/gskgpucolorizeop.c',
+  'gpu/gskgpucolorop.c',
   'gpu/gskgpudownloadop.c',
   'gpu/gskgpudevice.c',
   'gpu/gskgpuframe.c',