GPUShader: Add selection id shader

This is to separate id drawing from standard color drawing.

2 files changed, 45 insertions, 0 deletions

diff --git a/source/blender/gpu/shaders/gpu_shader_3D_selection_id_vert.glsl b/source/blender/gpu/shaders/gpu_shader_3D_selection_id_vert.glsl
new file mode 100644
index 00000000000..9c6be69efce
--- /dev/null
+++ b/source/blender/gpu/shaders/gpu_shader_3D_selection_id_vert.glsl
@@ -0,0 +1,24 @@
+
+uniform mat4 ModelViewProjectionMatrix;
+
+in vec3 pos;
+
+#ifndef UNIFORM_ID
+uniform uint offset;
+in uint color;
+
+flat out vec4 id;
+#endif
+
+void main()
+{
+#ifndef UNIFORM_ID
+	id = vec4(
+		(((color + offset)      ) & uint(0xFF)) * (1.0f / 255.0f),
+		(((color + offset) >>  8) & uint(0xFF)) * (1.0f / 255.0f),
+		(((color + offset) >> 16) & uint(0xFF)) * (1.0f / 255.0f),
+		(((color + offset) >> 24)             ) * (1.0f / 255.0f));
+#endif
+
+	gl_Position = ModelViewProjectionMatrix * vec4(pos, 1.0);
+}
diff --git a/source/blender/gpu/shaders/gpu_shader_selection_id_frag.glsl b/source/blender/gpu/shaders/gpu_shader_selection_id_frag.glsl
new file mode 100644
index 00000000000..29fe9e9d8c7
--- /dev/null
+++ b/source/blender/gpu/shaders/gpu_shader_selection_id_frag.glsl
@@ -0,0 +1,21 @@
+
+#ifdef UNIFORM_ID
+uniform uint id;
+#else
+flat in vec4 id;
+#endif
+
+out vec4 fragColor;
+
+void main()
+{
+#ifdef UNIFORM_ID
+	fragColor = vec4(
+		((id      ) & uint(0xFF)) * (1.0f / 255.0f),
+		((id >>  8) & uint(0xFF)) * (1.0f / 255.0f),
+		((id >> 16) & uint(0xFF)) * (1.0f / 255.0f),
+		((id >> 24)             ) * (1.0f / 255.0f));
+#else
+	fragColor = id;
+#endif
+}