UI: Perf: Make icon_draw_texture use GWN_draw_primitive.

This bypass the use of immediate mode for theses drawcalls. Placement and
and icon select (via uvs) is done inside the vertex shader.

1 files changed, 35 insertions, 0 deletions

diff --git a/source/blender/gpu/shaders/gpu_shader_2D_image_rect_vert.glsl b/source/blender/gpu/shaders/gpu_shader_2D_image_rect_vert.glsl
new file mode 100644
index 00000000000..118f4e3b187
--- /dev/null
+++ b/source/blender/gpu/shaders/gpu_shader_2D_image_rect_vert.glsl
@@ -0,0 +1,35 @@
+/**
+ * Simple shader that just draw one icon at the specified location
+ * does not need any vertex input (producing less call to immBegin/End)
+ **/
+
+uniform mat4 ModelViewProjectionMatrix;
+uniform vec4 rect_icon;
+uniform vec4 rect_geom;
+
+out vec2 texCoord_interp;
+
+void main()
+{
+	vec2 uv;
+	vec2 co;
+	if (gl_VertexID == 0) {
+		co = rect_geom.xw;
+		uv = rect_icon.xw;
+	}
+	else if (gl_VertexID == 1) {
+		co = rect_geom.xy;
+		uv = rect_icon.xy;
+	}
+	else if (gl_VertexID == 2) {
+		co = rect_geom.zw;
+		uv = rect_icon.zw;
+	}
+	else {
+		co = rect_geom.zy;
+		uv = rect_icon.zy;
+	}
+
+	gl_Position = ModelViewProjectionMatrix * vec4(co, 0.0f, 1.0f);
+	texCoord_interp = uv;
+}