[Bf-blender-cvs] [1b5b899] blender2.8: OpenGL: add built-in GPU_SHADER_3D_DEPTH_ONLY

[Mike Erwin]

Commit: 1b5b899228bd63e34dd1c35ada8e0408983b8f38
Author: Mike Erwin
Date:   Tue Sep 13 02:51:38 2016 -0400
Branches: blender2.8
https://developer.blender.org/rB1b5b899228bd63e34dd1c35ada8e0408983b8f38

OpenGL: add built-in GPU_SHADER_3D_DEPTH_ONLY

We’re discussing several techniques that require a depth pre-pass.

===================================================================

M	source/blender/gpu/CMakeLists.txt
M	source/blender/gpu/GPU_shader.h
M	source/blender/gpu/intern/gpu_shader.c
R100	source/blender/gpu/shaders/gpu_shader_2D_uniform_color_vert.glsl	source/blender/gpu/shaders/gpu_shader_2D_no_color_vert.glsl
R100	source/blender/gpu/shaders/gpu_shader_3D_uniform_color_vert.glsl	source/blender/gpu/shaders/gpu_shader_3D_no_color_vert.glsl
A	source/blender/gpu/shaders/gpu_shader_depth_only_frag.glsl

===================================================================

diff --git a/source/blender/gpu/CMakeLists.txt b/source/blender/gpu/CMakeLists.txt
index 99ce3eb..50c2db2 100644
--- a/source/blender/gpu/CMakeLists.txt
+++ b/source/blender/gpu/CMakeLists.txt
@@ -113,13 +113,14 @@ set(SRC
 	intern/gpu_private.h
 )
 
+data_to_c_simple(shaders/gpu_shader_depth_only_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_uniform_color_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_flat_color_frag.glsl SRC)
-data_to_c_simple(shaders/gpu_shader_2D_uniform_color_vert.glsl SRC)
+data_to_c_simple(shaders/gpu_shader_2D_no_color_vert.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_2D_flat_color_vert.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_3D_uniform_color_vert.glsl SRC)
+data_to_c_simple(shaders/gpu_shader_3D_no_color_vert.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_3D_flat_color_vert.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_3D_smooth_color_vert.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_3D_smooth_color_frag.glsl SRC)
diff --git a/source/blender/gpu/GPU_shader.h b/source/blender/gpu/GPU_shader.h
index 367e134..2a1c5e0 100644
--- a/source/blender/gpu/GPU_shader.h
+++ b/source/blender/gpu/GPU_shader.h
@@ -98,6 +98,7 @@ typedef enum GPUBuiltinShader {
 	GPU_SHADER_3D_UNIFORM_COLOR,
 	GPU_SHADER_3D_FLAT_COLOR,
 	GPU_SHADER_3D_SMOOTH_COLOR,
+	GPU_SHADER_3D_DEPTH_ONLY,
 } GPUBuiltinShader;
 
 GPUShader *GPU_shader_get_builtin_shader(GPUBuiltinShader shader);
diff --git a/source/blender/gpu/intern/gpu_shader.c b/source/blender/gpu/intern/gpu_shader.c
index c95c427..9fe3c3a 100644
--- a/source/blender/gpu/intern/gpu_shader.c
+++ b/source/blender/gpu/intern/gpu_shader.c
@@ -46,13 +46,14 @@
 #define MAX_EXT_DEFINE_LENGTH 1024
 
 /* Non-generated shaders */
+extern char datatoc_gpu_shader_depth_only_frag_glsl[];
 extern char datatoc_gpu_shader_uniform_color_frag_glsl[];
 extern char datatoc_gpu_shader_flat_color_frag_glsl[];
-extern char datatoc_gpu_shader_2D_uniform_color_vert_glsl[];
+extern char datatoc_gpu_shader_2D_no_color_vert_glsl[];
 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_3D_uniform_color_vert_glsl[];
+extern char datatoc_gpu_shader_3D_no_color_vert_glsl[];
 extern char datatoc_gpu_shader_3D_flat_color_vert_glsl[];
 extern char datatoc_gpu_shader_3D_smooth_color_vert_glsl[];
 extern char datatoc_gpu_shader_3D_smooth_color_frag_glsl[];
@@ -90,6 +91,7 @@ static struct GPUShadersGlobal {
 		GPUShader *uniform_color_3D;
 		GPUShader *flat_color_3D;
 		GPUShader *smooth_color_3D;
+		GPUShader *depth_only_3D;
 	} shaders;
 } GG = {{NULL}};
 
@@ -625,7 +627,7 @@ GPUShader *GPU_shader_get_builtin_shader(GPUBuiltinShader shader)
 		case GPU_SHADER_2D_UNIFORM_COLOR:
 			if (!GG.shaders.uniform_color_2D)
 				GG.shaders.uniform_color_2D = GPU_shader_create(
-				        datatoc_gpu_shader_2D_uniform_color_vert_glsl,
+				        datatoc_gpu_shader_2D_no_color_vert_glsl,
 				        datatoc_gpu_shader_uniform_color_frag_glsl,
 				        NULL, NULL, NULL, 0, 0, 0);
 			retval = GG.shaders.uniform_color_2D;
@@ -649,7 +651,7 @@ GPUShader *GPU_shader_get_builtin_shader(GPUBuiltinShader shader)
 		case GPU_SHADER_3D_UNIFORM_COLOR:
 			if (!GG.shaders.uniform_color_3D)
 				GG.shaders.uniform_color_3D = GPU_shader_create(
-				        datatoc_gpu_shader_3D_uniform_color_vert_glsl,
+				        datatoc_gpu_shader_3D_no_color_vert_glsl,
 				        datatoc_gpu_shader_uniform_color_frag_glsl,
 				        NULL, NULL, NULL, 0, 0, 0);
 			retval = GG.shaders.uniform_color_3D;
@@ -670,6 +672,14 @@ GPUShader *GPU_shader_get_builtin_shader(GPUBuiltinShader shader)
 				        NULL, NULL, NULL, 0, 0, 0);
 			retval = GG.shaders.smooth_color_3D;
 			break;
+		case GPU_SHADER_3D_DEPTH_ONLY:
+			if (!GG.shaders.depth_only_3D)
+				GG.shaders.depth_only_3D = GPU_shader_create(
+				        datatoc_gpu_shader_3D_no_color_vert_glsl,
+				        datatoc_gpu_shader_depth_only_frag_glsl,
+				        NULL, NULL, NULL, 0, 0, 0);
+			retval = GG.shaders.depth_only_3D;
+			break;
 	}
 
 	if (retval == NULL)
diff --git a/source/blender/gpu/shaders/gpu_shader_2D_uniform_color_vert.glsl b/source/blender/gpu/shaders/gpu_shader_2D_no_color_vert.glsl
similarity index 100%
rename from source/blender/gpu/shaders/gpu_shader_2D_uniform_color_vert.glsl
rename to source/blender/gpu/shaders/gpu_shader_2D_no_color_vert.glsl
diff --git a/source/blender/gpu/shaders/gpu_shader_3D_uniform_color_vert.glsl b/source/blender/gpu/shaders/gpu_shader_3D_no_color_vert.glsl
similarity index 100%
rename from source/blender/gpu/shaders/gpu_shader_3D_uniform_color_vert.glsl
rename to source/blender/gpu/shaders/gpu_shader_3D_no_color_vert.glsl
diff --git a/source/blender/gpu/shaders/gpu_shader_depth_only_frag.glsl b/source/blender/gpu/shaders/gpu_shader_depth_only_frag.glsl
new file mode 100644
index 0000000..60e71e1
--- /dev/null
+++ b/source/blender/gpu/shaders/gpu_shader_depth_only_frag.glsl
@@ -0,0 +1,6 @@
+
+void main()
+{
+	// no color output, only depth (line below is implicit)
+	// gl_FragDepth = gl_FragCoord.z;
+}