4 files changed, 229 insertions, 0 deletions
diff --git a/source/blender/gpu/GPU_draw.h b/source/blender/gpu/GPU_draw.h
index bc732387c85..90b65af87c8 100644
--- a/source/blender/gpu/GPU_draw.h
+++ b/source/blender/gpu/GPU_draw.h
@@ -160,6 +160,12 @@ struct DerivedMesh;
 void GPU_draw_update_fvar_offset(struct DerivedMesh *dm);
 #endif
 
+/* 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);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/blender/gpu/intern/gpu_draw.c b/source/blender/gpu/intern/gpu_draw.c
index 52177b756c5..3ea64e1f6d5 100644
--- a/source/blender/gpu/intern/gpu_draw.c
+++ b/source/blender/gpu/intern/gpu_draw.c
@@ -2327,3 +2327,152 @@ void GPU_draw_update_fvar_offset(DerivedMesh *dm)
 	}
 }
 #endif
+
+
+/** \name Framebuffer color depth, for selection codes
+ * \{ */
+
+#ifdef __APPLE__
+
+/* apple seems to round colors to below and up on some configs */
+
+static unsigned int index_to_framebuffer(int index)
+{
+	unsigned int 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 unsigned int index_to_framebuffer(int index)
+{
+	unsigned int 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(unsigned int 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(unsigned int *col, const unsigned int 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) {
+		unsigned int 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
+}
+
+/** \} */
diff --git a/source/blender/gpu/shaders/gpu_shader_vertex.glsl b/source/blender/gpu/shaders/gpu_shader_vertex.glsl
index 9a6537b4f09..db0068d2f3d 100644
--- a/source/blender/gpu/shaders/gpu_shader_vertex.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_vertex.glsl
@@ -14,6 +14,9 @@ varying vec3 varnormal;
 varying float gl_ClipDistance[6];
 #endif
 
+
+/* Color, keep in sync with: gpu_shader_vertex_world.glsl */
+
 float srgb_to_linearrgb(float c)
 {
 	if (c < 0.04045)
@@ -76,6 +79,9 @@ void set_var_from_attr(vec4 attr, int info, out vec4 var)
 	}
 }
 
+/* end color code */
+
+
 void main()
 {
 #ifndef USE_OPENSUBDIV
diff --git a/source/blender/gpu/shaders/gpu_shader_vertex_world.glsl b/source/blender/gpu/shaders/gpu_shader_vertex_world.glsl
index 9dbcaeb7a32..d45a4b316a8 100644
--- a/source/blender/gpu/shaders/gpu_shader_vertex_world.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_vertex_world.glsl
@@ -2,6 +2,74 @@
 varying vec3 varposition;
 varying vec3 varnormal;
 
+
+/* Color, keep in sync with: gpu_shader_vertex.glsl */
+
+float srgb_to_linearrgb(float c)
+{
+	if (c < 0.04045)
+		return (c < 0.0) ? 0.0 : c * (1.0 / 12.92);
+	else
+		return pow((c + 0.055) * (1.0 / 1.055), 2.4);
+}
+
+void srgb_to_linearrgb(vec3 col_from, out vec3 col_to)
+{
+	col_to.r = srgb_to_linearrgb(col_from.r);
+	col_to.g = srgb_to_linearrgb(col_from.g);
+	col_to.b = srgb_to_linearrgb(col_from.b);
+}
+
+void srgb_to_linearrgb(vec4 col_from, out vec4 col_to)
+{
+	col_to.r = srgb_to_linearrgb(col_from.r);
+	col_to.g = srgb_to_linearrgb(col_from.g);
+	col_to.b = srgb_to_linearrgb(col_from.b);
+	col_to.a = col_from.a;
+}
+
+bool is_srgb(int info)
+{
+#ifdef USE_NEW_SHADING
+	return (info == 1)? true: false;
+#else
+	return false;
+#endif
+}
+
+void set_var_from_attr(float attr, int info, out float var)
+{
+	var = attr;
+}
+
+void set_var_from_attr(vec2 attr, int info, out vec2 var)
+{
+	var = attr;
+}
+
+void set_var_from_attr(vec3 attr, int info, out vec3 var)
+{
+	if (is_srgb(info)) {
+		srgb_to_linearrgb(attr, var);
+	}
+	else {
+		var = attr;
+	}
+}
+
+void set_var_from_attr(vec4 attr, int info, out vec4 var)
+{
+	if (is_srgb(info)) {
+		srgb_to_linearrgb(attr, var);
+	}
+	else {
+		var = attr;
+	}
+}
+
+/* end color code */
+
+
 void main()
 {
 	/* position does not need to be transformed, we already have it */