Realtime Compositor: Add basic color nodes

This patch implements the following nodes for the realtime compositor:

- Alpha over node.
- Bright contrast node.
- Color balance node.
- Color correction node.
- Exposure node.
- Gamma node.
- Hue correct node.
- Hue saturation value node.
- Invert node.
- Mix node.
- Posterize node.
- Time curve node.
- Vector curve node.

Differential Revision: https://developer.blender.org/D15228

Reviewed By: Clement Foucault

1 files changed, 16 insertions, 11 deletions

diff --git a/source/blender/nodes/shader/nodes/node_shader_mix_rgb.cc b/source/blender/nodes/shader/nodes/node_shader_mix_rgb.cc
index 12707623049..478a6812c36 100644
--- a/source/blender/nodes/shader/nodes/node_shader_mix_rgb.cc
+++ b/source/blender/nodes/shader/nodes/node_shader_mix_rgb.cc
@@ -32,7 +32,7 @@ static const char *gpu_shader_get_name(int mode)
     case MA_RAMP_SCREEN:
       return "mix_screen";
     case MA_RAMP_DIV:
-      return "mix_div";
+      return "mix_div_fallback";
     case MA_RAMP_DIFF:
       return "mix_diff";
     case MA_RAMP_DARK:
@@ -70,18 +70,23 @@ static int gpu_shader_mix_rgb(GPUMaterial *mat,
 {
   const char *name = gpu_shader_get_name(node->custom1);
 
-  if (name != nullptr) {
-    int ret = GPU_stack_link(mat, node, name, in, out);
-    if (ret && node->custom2 & SHD_MIXRGB_CLAMP) {
-      const float min[3] = {0.0f, 0.0f, 0.0f};
-      const float max[3] = {1.0f, 1.0f, 1.0f};
-      GPU_link(
-          mat, "clamp_color", out[0].link, GPU_constant(min), GPU_constant(max), &out[0].link);
-    }
-    return ret;
+  if (name == nullptr) {
+    return 0;
   }
 
-  return 0;
+  const float min = 0.0f;
+  const float max = 1.0f;
+  const GPUNodeLink *factor_link = in[0].link ? in[0].link : GPU_uniform(in[0].vec);
+  GPU_link(mat, "clamp_value", factor_link, GPU_constant(&min), GPU_constant(&max), &in[0].link);
+
+  int ret = GPU_stack_link(mat, node, name, in, out);
+
+  if (ret && node->custom2 & SHD_MIXRGB_CLAMP) {
+    const float min[3] = {0.0f, 0.0f, 0.0f};
+    const float max[3] = {1.0f, 1.0f, 1.0f};
+    GPU_link(mat, "clamp_color", out[0].link, GPU_constant(min), GPU_constant(max), &out[0].link);
+  }
+  return ret;
 }
 
 class MixRGBFunction : public fn::MultiFunction {