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.

source/blender/editors/interface/interface_icons.c

@@ -1029,31 +1029,18 @@ static void icon_draw_texture(
 
 	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, icongltex.id);
-	Gwn_VertFormat *format = immVertexFormat();
-	unsigned int pos = GWN_vertformat_attr_add(format, "pos", GWN_COMP_F32, 2, GWN_FETCH_FLOAT);
-	unsigned int texCoord = GWN_vertformat_attr_add(format, "texCoord", GWN_COMP_F32, 2, GWN_FETCH_FLOAT);
 
-	immBindBuiltinProgram(GPU_SHADER_2D_IMAGE_COLOR);
-	if (rgb) immUniformColor3fvAlpha(rgb, alpha);
-	else     immUniformColor4f(alpha, alpha, alpha, alpha);
+	GPUShader *shader = GPU_shader_get_builtin_shader(GPU_SHADER_2D_IMAGE_RECT_COLOR);
+	GPU_shader_bind(shader);
 
-	immUniform1i("image", 0);
+	if (rgb) glUniform4f(GPU_shader_get_builtin_uniform(shader, GWN_UNIFORM_COLOR), rgb[0], rgb[1], rgb[2], alpha);
+	else     glUniform4f(GPU_shader_get_builtin_uniform(shader, GWN_UNIFORM_COLOR), alpha, alpha, alpha, alpha);
 
-	immBegin(GWN_PRIM_TRI_STRIP, 4);
-	immAttrib2f(texCoord, x1, y2);
-	immVertex2f(pos, x, y + h);
+	glUniform1i(GPU_shader_get_uniform(shader, "image"), 0);
+	glUniform4f(GPU_shader_get_uniform(shader, "rect_icon"), x1, y1, x2, y2);
+	glUniform4f(GPU_shader_get_uniform(shader, "rect_geom"), x, y, x + w, y + h);
 
-	immAttrib2f(texCoord, x1, y1);
-	immVertex2f(pos, x, y);
-
-	immAttrib2f(texCoord, x2, y2);
-	immVertex2f(pos, x + w, y + h);
-
-	immAttrib2f(texCoord, x2, y1);
-	immVertex2f(pos, x + w, y);
-	immEnd();
-
-	immUnbindProgram();
+	GWN_draw_primitive(GWN_PRIM_TRI_STRIP, 4);
 
 	glBindTexture(GL_TEXTURE_2D, 0);
 }

source/blender/gpu/CMakeLists.txt

@@ -139,6 +139,7 @@ data_to_c_simple(shaders/gpu_shader_2D_line_dashed_geom.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_2D_smooth_color_vert.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_2D_smooth_color_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_2D_image_vert.glsl SRC)
+data_to_c_simple(shaders/gpu_shader_2D_image_rect_vert.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_linear_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_shuffle_color_frag.glsl SRC)

source/blender/gpu/GPU_shader.h

@@ -114,6 +114,7 @@ typedef enum GPUBuiltinShader {
 	GPU_SHADER_2D_IMAGE_COLOR,
 	GPU_SHADER_2D_IMAGE_ALPHA_COLOR,
 	GPU_SHADER_2D_IMAGE_ALPHA,
+	GPU_SHADER_2D_IMAGE_RECT_COLOR,
 	GPU_SHADER_2D_CHECKER,
 	GPU_SHADER_2D_DIAG_STRIPES,
 	/* for simple 3D drawing */

source/blender/gpu/intern/gpu_shader.c

@@ -65,6 +65,7 @@ extern char datatoc_gpu_shader_2D_flat_color_vert_glsl[];
 extern char datatoc_gpu_shader_2D_smooth_color_vert_glsl[];
 extern char datatoc_gpu_shader_2D_smooth_color_frag_glsl[];
 extern char datatoc_gpu_shader_2D_image_vert_glsl[];
+extern char datatoc_gpu_shader_2D_image_rect_vert_glsl[];
 
 extern char datatoc_gpu_shader_3D_image_vert_glsl[];
 extern char datatoc_gpu_shader_image_frag_glsl[];
@@ -698,6 +699,9 @@ GPUShader *GPU_shader_get_builtin_shader(GPUBuiltinShader shader)
 		                                datatoc_gpu_shader_image_modulate_alpha_frag_glsl },
 		[GPU_SHADER_2D_IMAGE_SHUFFLE_COLOR] = { datatoc_gpu_shader_2D_image_vert_glsl,
 		                                        datatoc_gpu_shader_image_shuffle_color_frag_glsl },
+		[GPU_SHADER_2D_IMAGE_RECT_COLOR] = { datatoc_gpu_shader_2D_image_rect_vert_glsl,
+		                                     datatoc_gpu_shader_image_color_frag_glsl },
+
 		[GPU_SHADER_3D_UNIFORM_COLOR] = { datatoc_gpu_shader_3D_vert_glsl, datatoc_gpu_shader_uniform_color_frag_glsl },
 		[GPU_SHADER_3D_UNIFORM_COLOR_U32] = { datatoc_gpu_shader_3D_vert_glsl, datatoc_gpu_shader_uniform_color_frag_glsl },
 		[GPU_SHADER_3D_FLAT_COLOR] = { datatoc_gpu_shader_3D_flat_color_vert_glsl,

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;
+}