OpenGL: tweak image shaders & code that uses them

- rename image shaders to describe exactly what they do
- rename inputs to match other built-in shaders
- set & use active texture unit
- no need to enable/disable textures with GLSL
- pull vertex format setup out of loops

10 files changed, 92 insertions, 86 deletions

diff --git a/source/blender/editors/space_view3d/drawobject.c b/source/blender/editors/space_view3d/drawobject.c
index 408d27e9648..02702af597e 100644
--- a/source/blender/editors/space_view3d/drawobject.c
+++ b/source/blender/editors/space_view3d/drawobject.c
@@ -675,11 +675,11 @@ static void draw_empty_image(Object *ob, const short dflag, const unsigned char
 		}
 
 		VertexFormat *format = immVertexFormat();
-		unsigned pos = add_attrib(format, "position", GL_FLOAT, 2, KEEP_FLOAT);
-		unsigned texCoord = add_attrib(format, "texcoord", GL_FLOAT, 2, KEEP_FLOAT);
-		immBindBuiltinProgram(GPU_SHADER_2D_TEXTURE_2D); /* TODO: rename GPU_SHADER_3D_IMAGE_2D_MODULATE_ALPHA */
+		unsigned pos = add_attrib(format, "pos", GL_FLOAT, 2, KEEP_FLOAT);
+		unsigned texCoord = add_attrib(format, "texCoord", GL_FLOAT, 2, KEEP_FLOAT);
+		immBindBuiltinProgram(GPU_SHADER_3D_IMAGE_MODULATE_ALPHA);
 		immUniform1f("alpha", ob_alpha);
-		immUniform1i("texture_map", texUnit); /* TODO: rename "image" */
+		immUniform1i("image", texUnit);
 
 		immBegin(GL_TRIANGLE_FAN, 4);
 		immAttrib2f(texCoord, 0.0f, 0.0f);
diff --git a/source/blender/gpu/CMakeLists.txt b/source/blender/gpu/CMakeLists.txt
index b2a7c784d4a..e960a817a55 100644
--- a/source/blender/gpu/CMakeLists.txt
+++ b/source/blender/gpu/CMakeLists.txt
@@ -133,9 +133,9 @@ data_to_c_simple(shaders/gpu_shader_2D_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_2D_texture_2D_frag.glsl SRC)
-data_to_c_simple(shaders/gpu_shader_2D_texture_rect_frag.glsl SRC)
-data_to_c_simple(shaders/gpu_shader_2D_texture_vert.glsl SRC)
+data_to_c_simple(shaders/gpu_shader_image_modulate_alpha_frag.glsl SRC)
+data_to_c_simple(shaders/gpu_shader_image_rect_modulate_alpha_frag.glsl SRC)
+data_to_c_simple(shaders/gpu_shader_3D_image_vert.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_3D_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)
diff --git a/source/blender/gpu/GPU_shader.h b/source/blender/gpu/GPU_shader.h
index d52a0a2965d..1fe0f6f9717 100644
--- a/source/blender/gpu/GPU_shader.h
+++ b/source/blender/gpu/GPU_shader.h
@@ -101,9 +101,9 @@ typedef enum GPUBuiltinShader {
 	GPU_SHADER_3D_FLAT_COLOR,
 	GPU_SHADER_3D_SMOOTH_COLOR,
 	GPU_SHADER_3D_DEPTH_ONLY,
-	/* basic 2D texture drawing */
-	GPU_SHADER_2D_TEXTURE_2D,
-	GPU_SHADER_2D_TEXTURE_RECT,
+	/* basic image drawing */
+	GPU_SHADER_3D_IMAGE_MODULATE_ALPHA,
+	GPU_SHADER_3D_IMAGE_RECT_MODULATE_ALPHA,
 	/* points */
 	GPU_SHADER_2D_POINT_FIXED_SIZE_UNIFORM_COLOR,
 	GPU_SHADER_2D_POINT_UNIFORM_SIZE_UNIFORM_COLOR_SMOOTH,
diff --git a/source/blender/gpu/intern/gpu_shader.c b/source/blender/gpu/intern/gpu_shader.c
index 464135426d2..e8ea6425d7b 100644
--- a/source/blender/gpu/intern/gpu_shader.c
+++ b/source/blender/gpu/intern/gpu_shader.c
@@ -53,9 +53,9 @@ extern char datatoc_gpu_shader_2D_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_2D_texture_vert_glsl[];
-extern char datatoc_gpu_shader_2D_texture_2D_frag_glsl[];
-extern char datatoc_gpu_shader_2D_texture_rect_frag_glsl[];
+extern char datatoc_gpu_shader_3D_image_vert_glsl[];
+extern char datatoc_gpu_shader_image_modulate_alpha_frag_glsl[];
+extern char datatoc_gpu_shader_image_rect_modulate_alpha_frag_glsl[];
 extern char datatoc_gpu_shader_3D_vert_glsl[];
 extern char datatoc_gpu_shader_3D_flat_color_vert_glsl[];
 extern char datatoc_gpu_shader_3D_smooth_color_vert_glsl[];
@@ -105,9 +105,9 @@ static struct GPUShadersGlobal {
 		GPUShader *fx_shaders[MAX_FX_SHADERS * 2];
 		/* for drawing text */
 		GPUShader *text;
-		/* for drawing texture */
-		GPUShader *texture_2D;
-		GPUShader *texture_rect;
+		/* for drawing images */
+		GPUShader *image_modulate_alpha_3D;
+		GPUShader *image_rect_modulate_alpha_3D;
 		/* for simple 2D drawing */
 		GPUShader *uniform_color_2D;
 		GPUShader *flat_color_2D;
@@ -651,21 +651,21 @@ GPUShader *GPU_shader_get_builtin_shader(GPUBuiltinShader shader)
 				        NULL, NULL, NULL, 0, 0, 0);
 			retval = GG.shaders.text;
 			break;
-		case GPU_SHADER_2D_TEXTURE_2D:
-			if (!GG.shaders.texture_2D)
-				GG.shaders.texture_2D = GPU_shader_create(
-				        datatoc_gpu_shader_2D_texture_vert_glsl,
-				        datatoc_gpu_shader_2D_texture_2D_frag_glsl,
+		case GPU_SHADER_3D_IMAGE_MODULATE_ALPHA:
+			if (!GG.shaders.image_modulate_alpha_3D)
+				GG.shaders.image_modulate_alpha_3D = GPU_shader_create(
+				        datatoc_gpu_shader_3D_image_vert_glsl,
+				        datatoc_gpu_shader_image_modulate_alpha_frag_glsl,
 				        NULL, NULL, NULL, 0, 0, 0);
-			retval = GG.shaders.texture_2D;
+			retval = GG.shaders.image_modulate_alpha_3D;
 			break;
-		case GPU_SHADER_2D_TEXTURE_RECT:
-			if (!GG.shaders.texture_rect)
-				GG.shaders.texture_rect = GPU_shader_create(
-				datatoc_gpu_shader_2D_texture_vert_glsl,
-				datatoc_gpu_shader_2D_texture_rect_frag_glsl,
+		case GPU_SHADER_3D_IMAGE_RECT_MODULATE_ALPHA:
+			if (!GG.shaders.image_rect_modulate_alpha_3D)
+				GG.shaders.image_rect_modulate_alpha_3D = GPU_shader_create(
+				datatoc_gpu_shader_3D_image_vert_glsl,
+				datatoc_gpu_shader_image_rect_modulate_alpha_frag_glsl,
 				NULL, NULL, NULL, 0, 0, 0);
-			retval = GG.shaders.texture_rect;
+			retval = GG.shaders.image_rect_modulate_alpha_3D;
 			break;
 		case GPU_SHADER_2D_UNIFORM_COLOR:
 			if (!GG.shaders.uniform_color_2D)
@@ -917,14 +917,14 @@ void GPU_shader_free_builtin_shaders(void)
 		GG.shaders.text = NULL;
 	}
 
-	if (GG.shaders.texture_2D) {
-		GPU_shader_free(GG.shaders.texture_2D);
-		GG.shaders.texture_2D = NULL;
+	if (GG.shaders.image_modulate_alpha_3D) {
+		GPU_shader_free(GG.shaders.image_modulate_alpha_3D);
+		GG.shaders.image_modulate_alpha_3D = NULL;
 	}
 
-	if (GG.shaders.texture_rect) {
-		GPU_shader_free(GG.shaders.texture_rect);
-		GG.shaders.texture_rect = NULL;
+	if (GG.shaders.image_rect_modulate_alpha_3D) {
+		GPU_shader_free(GG.shaders.image_rect_modulate_alpha_3D);
+		GG.shaders.image_rect_modulate_alpha_3D = NULL;
 	}
 
 	if (GG.shaders.uniform_color_2D) {
diff --git a/source/blender/gpu/shaders/gpu_shader_2D_texture_vert.glsl b/source/blender/gpu/shaders/gpu_shader_2D_texture_vert.glsl
deleted file mode 100644
index 4c05cf1d25b..00000000000
--- a/source/blender/gpu/shaders/gpu_shader_2D_texture_vert.glsl
+++ /dev/null
@@ -1,19 +0,0 @@
-
-uniform mat4 ModelViewProjectionMatrix;
-
-#if __VERSION__ == 120
-  attribute vec2 texcoord;
-  attribute vec3 position;
-  varying vec2 texture_coord;
-#else
-  in vec2 texcoord;
-  in vec3 position;
-  out vec2 texture_coord;
-#endif
-
-
-void main()
-{
-	gl_Position = ModelViewProjectionMatrix * vec4(position.xyz, 1.0f);
-	texture_coord = texcoord;
-}
diff --git a/source/blender/gpu/shaders/gpu_shader_3D_image_vert.glsl b/source/blender/gpu/shaders/gpu_shader_3D_image_vert.glsl
new file mode 100644
index 00000000000..e9f847f28b3
--- /dev/null
+++ b/source/blender/gpu/shaders/gpu_shader_3D_image_vert.glsl
@@ -0,0 +1,18 @@
+
+uniform mat4 ModelViewProjectionMatrix;
+
+#if __VERSION__ == 120
+  attribute vec2 texCoord;
+  attribute vec3 pos;
+  varying vec2 texCoord_interp;
+#else
+  in vec2 texCoord;
+  in vec3 pos;
+  out vec2 texCoord_interp;
+#endif
+
+void main()
+{
+	gl_Position = ModelViewProjectionMatrix * vec4(pos.xyz, 1.0f);
+	texCoord_interp = texCoord;
+}
diff --git a/source/blender/gpu/shaders/gpu_shader_2D_texture_2D_frag.glsl b/source/blender/gpu/shaders/gpu_shader_image_modulate_alpha_frag.glsl
index cd4f0d2f4c5..74e17198985 100644
--- a/source/blender/gpu/shaders/gpu_shader_2D_texture_2D_frag.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_image_modulate_alpha_frag.glsl
@@ -1,17 +1,18 @@
+
 #if __VERSION__ == 120
-  varying vec2 texture_coord;
+  varying vec2 texCoord_interp;
   #define fragColor gl_FragColor
 #else
-  in vec2 texture_coord;
+  in vec2 texCoord_interp;
   out vec4 fragColor;
   #define texture2D texture
 #endif
 
 uniform float alpha;
-uniform sampler2D texture_map;
+uniform sampler2D image;
 
 void main()
 {
-	fragColor = texture2D(texture_map, texture_coord);
+	fragColor = texture2D(image, texCoord_interp);
 	fragColor.a *= alpha;
 }
diff --git a/source/blender/gpu/shaders/gpu_shader_2D_texture_rect_frag.glsl b/source/blender/gpu/shaders/gpu_shader_image_rect_modulate_alpha_frag.glsl
index 9dad41dd832..aae3b40efd4 100644
--- a/source/blender/gpu/shaders/gpu_shader_2D_texture_rect_frag.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_image_rect_modulate_alpha_frag.glsl
@@ -1,17 +1,18 @@
+
 #if __VERSION__ == 120
-  varying vec2 texture_coord;
+  varying vec2 texCoord_interp;
   #define fragColor gl_FragColor
 #else
-  in vec2 texture_coord;
+  in vec2 texCoord_interp;
   out vec4 fragColor;
   #define texture2DRect texture
 #endif
 
 uniform float alpha;
-uniform sampler2DRect texture_map;
+uniform sampler2DRect image;
 
 void main()
 {
-	fragColor = texture2DRect(texture_map, texture_coord);
+	fragColor = texture2DRect(image, texCoord_interp);
 	fragColor.a *= alpha;
 }
diff --git a/source/blender/windowmanager/intern/wm_draw.c b/source/blender/windowmanager/intern/wm_draw.c
index e9eaa5677e4..f38f1eee7ec 100644
--- a/source/blender/windowmanager/intern/wm_draw.c
+++ b/source/blender/windowmanager/intern/wm_draw.c
@@ -447,16 +447,16 @@ void wm_triple_draw_textures(wmWindow *win, wmDrawTriple *triple, float alpha)
 	}
 
 	VertexFormat *format = immVertexFormat();
-	unsigned texcoord = add_attrib(format, "texcoord", GL_FLOAT, 2, KEEP_FLOAT);
-	unsigned pos = add_attrib(format, "position", GL_FLOAT, 2, KEEP_FLOAT);
-
-	glEnable(triple->target);
-	immBindBuiltinProgram((triple->target == GL_TEXTURE_2D) ? GPU_SHADER_2D_TEXTURE_2D : GPU_SHADER_2D_TEXTURE_RECT);
+	unsigned texcoord = add_attrib(format, "texCoord", GL_FLOAT, 2, KEEP_FLOAT);
+	unsigned pos = add_attrib(format, "pos", GL_FLOAT, 2, KEEP_FLOAT);
 
+	const int activeTex = GL_TEXTURE0;
+	glActiveTexture(activeTex);
 	glBindTexture(triple->target, triple->bind);
 
+	immBindBuiltinProgram((triple->target == GL_TEXTURE_2D) ? GPU_SHADER_3D_IMAGE_MODULATE_ALPHA : GPU_SHADER_3D_IMAGE_RECT_MODULATE_ALPHA);
 	immUniform1f("alpha", alpha);
-	immUniform1i("texture_map", 0);
+	immUniform1i("image", activeTex);
 
 	immBegin(GL_QUADS, 4);
 
@@ -476,7 +476,6 @@ void wm_triple_draw_textures(wmWindow *win, wmDrawTriple *triple, float alpha)
 	immUnbindProgram();
 
 	glBindTexture(triple->target, 0);
-	glDisable(triple->target);
 }
 
 static void wm_triple_copy_textures(wmWindow *win, wmDrawTriple *triple)
diff --git a/source/blender/windowmanager/intern/wm_stereo.c b/source/blender/windowmanager/intern/wm_stereo.c
index e2b6df65ce8..c72bd676364 100644
--- a/source/blender/windowmanager/intern/wm_stereo.c
+++ b/source/blender/windowmanager/intern/wm_stereo.c
@@ -173,6 +173,13 @@ static void wm_method_draw_stereo3d_sidebyside(wmWindow *win)
 	int soffx;
 	bool cross_eyed = (win->stereo3d_format->flag & S3D_SIDEBYSIDE_CROSSEYED) != 0;
 
+	const int activeTex = GL_TEXTURE0;
+	glActiveTexture(activeTex);
+
+	VertexFormat *format = immVertexFormat();
+	unsigned texcoord = add_attrib(format, "texCoord", GL_FLOAT, 2, KEEP_FLOAT);
+	unsigned pos = add_attrib(format, "pos", GL_FLOAT, 2, KEEP_FLOAT);
+
 	for (view = 0; view < 2; view ++) {
 		drawdata = BLI_findlink(&win->drawdata, (view * 2) + 1);
 		triple = drawdata->triple;
@@ -204,16 +211,12 @@ static void wm_method_draw_stereo3d_sidebyside(wmWindow *win)
 			halfy /= triple->y;
 		}
 
-		VertexFormat *format = immVertexFormat();
-		unsigned texcoord = add_attrib(format, "texcoord", GL_FLOAT, 2, KEEP_FLOAT);
-		unsigned pos = add_attrib(format, "position", GL_FLOAT, 2, KEEP_FLOAT);
-
-		glEnable(triple->target);
-		immBindBuiltinProgram((triple->target == GL_TEXTURE_2D) ? GPU_SHADER_2D_TEXTURE_2D : GPU_SHADER_2D_TEXTURE_RECT);
+		/* TODO: if target is always same for both eyes, bind program & set uniform before loop */
+		immBindBuiltinProgram((triple->target == GL_TEXTURE_2D) ? GPU_SHADER_3D_IMAGE_MODULATE_ALPHA : GPU_SHADER_3D_IMAGE_RECT_MODULATE_ALPHA);
 
 		glBindTexture(triple->target, triple->bind);
 
-		immUniform1i("texture_map", 0);
+		immUniform1i("image", activeTex);
 
 		immBegin(GL_QUADS, 4);
 
@@ -230,10 +233,10 @@ static void wm_method_draw_stereo3d_sidebyside(wmWindow *win)
 		immVertex2f(pos, soffx, sizey);
 
 		immEnd();
-		immUnbindProgram();
 
+		/* TODO: if target is always same for both eyes, unbind program & texture target after loop */
 		glBindTexture(triple->target, 0);
-		glDisable(triple->target);
+		immUnbindProgram();
 	}
 }
 
@@ -245,6 +248,13 @@ static void wm_method_draw_stereo3d_topbottom(wmWindow *win)
 	int view;
 	int soffy;
 
+	const int activeTex = GL_TEXTURE0;
+	glActiveTexture(activeTex);
+
+	VertexFormat *format = immVertexFormat();
+	unsigned texcoord = add_attrib(format, "texCoord", GL_FLOAT, 2, KEEP_FLOAT);
+	unsigned pos = add_attrib(format, "pos", GL_FLOAT, 2, KEEP_FLOAT);
+
 	for (view = 0; view < 2; view ++) {
 		drawdata = BLI_findlink(&win->drawdata, (view * 2) + 1);
 		triple = drawdata->triple;
@@ -273,17 +283,13 @@ static void wm_method_draw_stereo3d_topbottom(wmWindow *win)
 			halfy /= triple->y;
 		}
 
-		VertexFormat *format = immVertexFormat();
-		unsigned texcoord = add_attrib(format, "texcoord", GL_FLOAT, 2, KEEP_FLOAT);
-		unsigned pos = add_attrib(format, "position", GL_FLOAT, 2, KEEP_FLOAT);
-
-		glEnable(triple->target);
-		immBindBuiltinProgram((triple->target == GL_TEXTURE_2D) ? GPU_SHADER_2D_TEXTURE_2D : GPU_SHADER_2D_TEXTURE_RECT);
+		/* TODO: if target is always same for both eyes, bind program & set uniforms before loop */
+		immBindBuiltinProgram((triple->target == GL_TEXTURE_2D) ? GPU_SHADER_3D_IMAGE_MODULATE_ALPHA : GPU_SHADER_3D_IMAGE_RECT_MODULATE_ALPHA);
 
 		glBindTexture(triple->target, triple->bind);
 
 		immUniform1f("alpha", 1.0f);
-		immUniform1i("texture_map", 0);
+		immUniform1i("image", activeTex);
 
 		immBegin(GL_QUADS, 4);
 
@@ -300,10 +306,10 @@ static void wm_method_draw_stereo3d_topbottom(wmWindow *win)
 		immVertex2f(pos, 0.0f, soffy + (sizey * 0.5f));
 
 		immEnd();
-		immUnbindProgram();
 
+		/* TODO: if target is always same for both eyes, unbind program & texture target after loop */
+		immUnbindProgram();
 		glBindTexture(triple->target, 0);
-		glDisable(triple->target);
 	}
 }