GPU: Simplify select shaders.

The shaders are: `GPU_SHADER_3D_FLAT_SELECT_ID` and `GPU_SHADER_3D_UNIFORM_SELECT_ID`.
This commit allows the drawing of the mesh select ids to be done on a 32UI format texture.
This simplifies the shader that previously acted on the backbuffer and had to do an uint to rgba conversion.

Differential Revision: https://developer.blender.org/D4350

6 files changed, 4 insertions, 176 deletions

diff --git a/source/blender/gpu/GPU_draw.h b/source/blender/gpu/GPU_draw.h
index f9ea9a35084..ce9a20bcf7c 100644
--- a/source/blender/gpu/GPU_draw.h
+++ b/source/blender/gpu/GPU_draw.h
@@ -99,11 +99,6 @@ void GPU_create_smoke_velocity(struct SmokeModifierData *smd);
 void GPU_free_unused_buffers(struct Main *bmain);
 
 /* utilities */
-void	GPU_select_index_set(int index);
-void	GPU_select_index_get(int index, int *r_col);
-int		GPU_select_to_index(unsigned int col);
-void	GPU_select_to_index_array(unsigned int *col, const unsigned int size);
-
 typedef enum eGPUAttrMask {
 	GPU_DEPTH_BUFFER_BIT = (1 << 0),
 	GPU_ENABLE_BIT = (1 << 1),
diff --git a/source/blender/gpu/GPU_extensions.h b/source/blender/gpu/GPU_extensions.h
index 3154119592d..b656bb74d4b 100644
--- a/source/blender/gpu/GPU_extensions.h
+++ b/source/blender/gpu/GPU_extensions.h
@@ -42,7 +42,6 @@ int GPU_max_cube_map_size(void);
 int GPU_max_ubo_binds(void);
 int GPU_max_ubo_size(void);
 float GPU_max_line_width(void);
-int GPU_color_depth(void);
 void GPU_get_dfdy_factors(float fac[2]);
 bool GPU_mip_render_workaround(void);
 bool GPU_depth_blitting_workaround(void);
diff --git a/source/blender/gpu/intern/gpu_draw.c b/source/blender/gpu/intern/gpu_draw.c
index 62dcbb94d1c..d91ea234931 100644
--- a/source/blender/gpu/intern/gpu_draw.c
+++ b/source/blender/gpu/intern/gpu_draw.c
@@ -1275,148 +1275,6 @@ void GPU_disable_program_point_size(void)
 /** \name Framebuffer color depth, for selection codes
  * \{ */
 
-#ifdef __APPLE__
-
-/* apple seems to round colors to below and up on some configs */
-
-static uint index_to_framebuffer(int index)
-{
-	uint i = index;
-
-	switch (GPU_color_depth()) {
-		case 12:
-			i = ((i & 0xF00) << 12) + ((i & 0xF0) << 8) + ((i & 0xF) << 4);
-			/* sometimes dithering subtracts! */
-			i |= 0x070707;
-			break;
-		case 15:
-		case 16:
-			i = ((i & 0x7C00) << 9) + ((i & 0x3E0) << 6) + ((i & 0x1F) << 3);
-			i |= 0x030303;
-			break;
-		case 24:
-			break;
-		default: /* 18 bits... */
-			i = ((i & 0x3F000) << 6) + ((i & 0xFC0) << 4) + ((i & 0x3F) << 2);
-			i |= 0x010101;
-			break;
-	}
-
-	return i;
-}
-
-#else
-
-/* this is the old method as being in use for ages.... seems to work? colors are rounded to lower values */
-
-static uint index_to_framebuffer(int index)
-{
-	uint i = index;
-
-	switch (GPU_color_depth()) {
-		case 8:
-			i = ((i & 48) << 18) + ((i & 12) << 12) + ((i & 3) << 6);
-			i |= 0x3F3F3F;
-			break;
-		case 12:
-			i = ((i & 0xF00) << 12) + ((i & 0xF0) << 8) + ((i & 0xF) << 4);
-			/* sometimes dithering subtracts! */
-			i |= 0x0F0F0F;
-			break;
-		case 15:
-		case 16:
-			i = ((i & 0x7C00) << 9) + ((i & 0x3E0) << 6) + ((i & 0x1F) << 3);
-			i |= 0x070707;
-			break;
-		case 24:
-			break;
-		default:    /* 18 bits... */
-			i = ((i & 0x3F000) << 6) + ((i & 0xFC0) << 4) + ((i & 0x3F) << 2);
-			i |= 0x030303;
-			break;
-	}
-
-	return i;
-}
-
-#endif
-
-
-void GPU_select_index_set(int index)
-{
-	const int col = index_to_framebuffer(index);
-	glColor3ub(( (col)        & 0xFF),
-	           (((col) >>  8) & 0xFF),
-	           (((col) >> 16) & 0xFF));
-}
-
-void GPU_select_index_get(int index, int *r_col)
-{
-	const int col = index_to_framebuffer(index);
-	char *c_col = (char *)r_col;
-	c_col[0] = (col & 0xFF); /* red */
-	c_col[1] = ((col >>  8) & 0xFF); /* green */
-	c_col[2] = ((col >> 16) & 0xFF); /* blue */
-	c_col[3] = 0xFF; /* alpha */
-}
-
-
-#define INDEX_FROM_BUF_8(col)     ((((col) & 0xC00000) >> 18) + (((col) & 0xC000) >> 12) + (((col) & 0xC0) >> 6))
-#define INDEX_FROM_BUF_12(col)    ((((col) & 0xF00000) >> 12) + (((col) & 0xF000) >> 8)  + (((col) & 0xF0) >> 4))
-#define INDEX_FROM_BUF_15_16(col) ((((col) & 0xF80000) >> 9)  + (((col) & 0xF800) >> 6)  + (((col) & 0xF8) >> 3))
-#define INDEX_FROM_BUF_18(col)    ((((col) & 0xFC0000) >> 6)  + (((col) & 0xFC00) >> 4)  + (((col) & 0xFC) >> 2))
-#define INDEX_FROM_BUF_24(col)      ((col) & 0xFFFFFF)
-
-int GPU_select_to_index(uint col)
-{
-	if (col == 0) {
-		return 0;
-	}
-
-	switch (GPU_color_depth()) {
-		case  8: return INDEX_FROM_BUF_8(col);
-		case 12: return INDEX_FROM_BUF_12(col);
-		case 15:
-		case 16: return INDEX_FROM_BUF_15_16(col);
-		case 24: return INDEX_FROM_BUF_24(col);
-		default: return INDEX_FROM_BUF_18(col);
-	}
-}
-
-void GPU_select_to_index_array(uint *col, const uint size)
-{
-#define INDEX_BUF_ARRAY(INDEX_FROM_BUF_BITS) \
-	for (i = size; i--; col++) { \
-		if ((c = *col)) { \
-			*col = INDEX_FROM_BUF_BITS(c); \
-		} \
-	} ((void)0)
-
-	if (size > 0) {
-		uint i, c;
-
-		switch (GPU_color_depth()) {
-			case  8:
-				INDEX_BUF_ARRAY(INDEX_FROM_BUF_8);
-				break;
-			case 12:
-				INDEX_BUF_ARRAY(INDEX_FROM_BUF_12);
-				break;
-			case 15:
-			case 16:
-				INDEX_BUF_ARRAY(INDEX_FROM_BUF_15_16);
-				break;
-			case 24:
-				INDEX_BUF_ARRAY(INDEX_FROM_BUF_24);
-				break;
-			default:
-				INDEX_BUF_ARRAY(INDEX_FROM_BUF_18);
-				break;
-		}
-	}
-
-#undef INDEX_BUF_ARRAY
-}
 
 #define STATE_STACK_DEPTH 16
 
diff --git a/source/blender/gpu/intern/gpu_extensions.c b/source/blender/gpu/intern/gpu_extensions.c
index 6fb40b06177..282b9dfc388 100644
--- a/source/blender/gpu/intern/gpu_extensions.c
+++ b/source/blender/gpu/intern/gpu_extensions.c
@@ -67,7 +67,6 @@ static struct GPUGlobal {
 	GLint maxtexturesvert;
 	GLint maxubosize;
 	GLint maxubobinds;
-	int colordepth;
 	int samples_color_texture_max;
 	eGPUDeviceType device;
 	eGPUOSType os;
@@ -252,12 +251,6 @@ void gpu_extensions_init(void)
 	BLI_assert(ret == GL_FRAMEBUFFER_DEFAULT);
 #endif
 
-	GLint r, g, b;
-	glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_FRONT_LEFT, GL_FRAMEBUFFER_ATTACHMENT_RED_SIZE, &r);
-	glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_FRONT_LEFT, GL_FRAMEBUFFER_ATTACHMENT_GREEN_SIZE, &g);
-	glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_FRONT_LEFT, GL_FRAMEBUFFER_ATTACHMENT_BLUE_SIZE, &b);
-	GG.colordepth = r + g + b; /* Assumes same depth for RGB. */
-
 	glGetIntegerv(GL_MAX_COLOR_TEXTURE_SAMPLES, &GG.samples_color_texture_max);
 
 	const char *vendor = (const char *)glGetString(GL_VENDOR);
@@ -402,11 +395,6 @@ void gpu_extensions_exit(void)
 	GPU_invalid_tex_free();
 }
 
-int GPU_color_depth(void)
-{
-	return GG.colordepth;
-}
-
 bool GPU_mem_stats_supported(void)
 {
 	return (GLEW_NVX_gpu_memory_info || GLEW_ATI_meminfo) && (G.debug & G_DEBUG_GPU_MEM);
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
index b2d186efa91..bdb26981399 100644
--- a/source/blender/gpu/shaders/gpu_shader_3D_selection_id_vert.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_3D_selection_id_vert.glsl
@@ -7,17 +7,13 @@ in vec3 pos;
 uniform uint offset;
 in uint color;
 
-flat out vec4 id;
+flat out uint id;
 #endif
 
 void main()
 {
 #ifndef UNIFORM_ID
-	id = vec4(
-		(((color + offset)       ) & 0xFFu) * (1.0f / 255.0f),
-		(((color + offset) >>  8u) & 0xFFu) * (1.0f / 255.0f),
-		(((color + offset) >> 16u) & 0xFFu) * (1.0f / 255.0f),
-		(((color + offset) >> 24u)        ) * (1.0f / 255.0f));
+	id = offset + color;
 #endif
 
 	vec4 pos_4d = 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
index a38113fad87..45ba6cf4d08 100644
--- a/source/blender/gpu/shaders/gpu_shader_selection_id_frag.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_selection_id_frag.glsl
@@ -2,20 +2,12 @@
 #ifdef UNIFORM_ID
 uniform uint id;
 #else
-flat in vec4 id;
+flat in uint id;
 #endif
 
-out vec4 fragColor;
+out uint fragColor;
 
 void main()
 {
-#ifdef UNIFORM_ID
-	fragColor = vec4(
-		((id       ) & 0xFFu) * (1.0f / 255.0f),
-		((id >>  8u) & 0xFFu) * (1.0f / 255.0f),
-		((id >> 16u) & 0xFFu) * (1.0f / 255.0f),
-		((id >> 24u)        ) * (1.0f / 255.0f));
-#else
 	fragColor = id;
-#endif
 }