OpenGL: transition to ARB FBOs, remove runtime checks

ARB_framebuffer_object replaces several related EXT extensions. The ARB
version pulls GL 3 FBO features into GL 2.1, useful for Mac platform.
Its functions and enums have no ARB suffix so transition to modern GL
will be seamless!

Extension is checked at startup, so is guaranteed to be true at runtime.

Part of T49012

5 files changed, 58 insertions, 78 deletions

diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index 3fa95315eba..02e60096348 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -1434,7 +1434,7 @@ void view3d_opengl_read_pixels(ARegion *ar, int x, int y, int w, int h, int form
 
 	if (rv3d->gpuoffscreen) {
 		GPU_offscreen_bind(rv3d->gpuoffscreen, true);
-		glReadBuffer(GL_COLOR_ATTACHMENT0_EXT);
+		glReadBuffer(GL_COLOR_ATTACHMENT0);
 		glReadPixels(x, y, w, h, format, type, data);
 		GPU_offscreen_unbind(rv3d->gpuoffscreen, true);
 	}
diff --git a/source/blender/gpu/intern/gpu_compositing.c b/source/blender/gpu/intern/gpu_compositing.c
index 964c2b5051e..aabe96de98d 100644
--- a/source/blender/gpu/intern/gpu_compositing.c
+++ b/source/blender/gpu/intern/gpu_compositing.c
@@ -382,9 +382,6 @@ bool GPU_fx_compositor_initialize_passes(
 
 	fx->effects = 0;
 
-	if (!GLEW_EXT_framebuffer_object)
-		return false;
-
 	if (!fx_settings) {
 		cleanup_fx_gl_data(fx, true);
 		return false;
diff --git a/source/blender/gpu/intern/gpu_draw.c b/source/blender/gpu/intern/gpu_draw.c
index 1c2dbfb8085..25b28b1f7d2 100644
--- a/source/blender/gpu/intern/gpu_draw.c
+++ b/source/blender/gpu/intern/gpu_draw.c
@@ -277,7 +277,7 @@ void GPU_set_gpu_mipmapping(int gpu_mipmap)
 	int old_value = GTS.gpu_mipmap;
 
 	/* only actually enable if it's supported */
-	GTS.gpu_mipmap = gpu_mipmap && GLEW_EXT_framebuffer_object;
+	GTS.gpu_mipmap = gpu_mipmap;
 
 	if (old_value != GTS.gpu_mipmap) {
 		GPU_free_images();
@@ -297,11 +297,7 @@ static void gpu_generate_mipmap(GLenum target)
 			glEnable(target);
 	}
 
-	/* TODO: simplify when we transition to GL >= 3 */
-	if (GLEW_VERSION_3_0 || GLEW_ARB_framebuffer_object)
-		glGenerateMipmap(target);
-	else if (GLEW_EXT_framebuffer_object)
-		glGenerateMipmapEXT(target);
+	glGenerateMipmap(target);
 
 	if (is_ati && !target_enabled)
 		glDisable(target);
diff --git a/source/blender/gpu/intern/gpu_extensions.c b/source/blender/gpu/intern/gpu_extensions.c
index ff0fd42b56c..c2190bca5f7 100644
--- a/source/blender/gpu/intern/gpu_extensions.c
+++ b/source/blender/gpu/intern/gpu_extensions.c
@@ -56,10 +56,8 @@
 /* Extensions support */
 
 /* -- extension: version of GL that absorbs it
+ * EXT_gpu_shader4: 3.0
  * ARB_framebuffer object: 3.0
- * EXT_framebuffer_object: 3.0
- * EXT_framebuffer_blit: 3.0
- * EXT_framebuffer_multisample: 3.0
  * EXT_framebuffer_multisample_blit_scaled: ???
  * ARB_draw_instanced: 3.1
  * ARB_texture_multisample: 3.2
diff --git a/source/blender/gpu/intern/gpu_framebuffer.c b/source/blender/gpu/intern/gpu_framebuffer.c
index c0400cdb04c..b34b940f547 100644
--- a/source/blender/gpu/intern/gpu_framebuffer.c
+++ b/source/blender/gpu/intern/gpu_framebuffer.c
@@ -57,30 +57,30 @@ static void GPU_print_framebuffer_error(GLenum status, char err_out[256])
 	const char *err = "unknown";
 
 	switch (status) {
-		case GL_FRAMEBUFFER_COMPLETE_EXT:
+		case GL_FRAMEBUFFER_COMPLETE:
 			break;
 		case GL_INVALID_OPERATION:
 			err = "Invalid operation";
 			break;
-		case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT:
+		case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
 			err = "Incomplete attachment";
 			break;
-		case GL_FRAMEBUFFER_UNSUPPORTED_EXT:
+		case GL_FRAMEBUFFER_UNSUPPORTED:
 			err = "Unsupported framebuffer format";
 			break;
-		case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT:
+		case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
 			err = "Missing attachment";
 			break;
-		case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT:
+		case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS:
 			err = "Attached images must have same dimensions";
 			break;
-		case GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT:
+		case GL_FRAMEBUFFER_INCOMPLETE_FORMATS:
 			err = "Attached images must have same format";
 			break;
-		case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT:
+		case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER:
 			err = "Missing draw buffer";
 			break;
-		case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT:
+		case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER:
 			err = "Missing read buffer";
 			break;
 	}
@@ -101,14 +101,8 @@ GPUFrameBuffer *GPU_framebuffer_create(void)
 {
 	GPUFrameBuffer *fb;
 
-	if (!(GLEW_VERSION_3_0 || GLEW_ARB_framebuffer_object ||
-	      (GLEW_EXT_framebuffer_object && GLEW_EXT_framebuffer_blit)))
-	{
-		return NULL;
-	}
-	
 	fb = MEM_callocN(sizeof(GPUFrameBuffer), "GPUFrameBuffer");
-	glGenFramebuffersEXT(1, &fb->object);
+	glGenFramebuffers(1, &fb->object);
 
 	if (!fb->object) {
 		fprintf(stderr, "GPUFFrameBuffer: framebuffer gen failed. %d\n",
@@ -118,10 +112,10 @@ GPUFrameBuffer *GPU_framebuffer_create(void)
 	}
 
 	/* make sure no read buffer is enabled, so completeness check will not fail. We set those at binding time */
-	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb->object);
+	glBindFramebuffer(GL_FRAMEBUFFER, fb->object);
 	glReadBuffer(GL_NONE);
 	glDrawBuffer(GL_NONE);
-	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
 	
 	return fb;
 }
@@ -147,17 +141,17 @@ int GPU_framebuffer_texture_attach(GPUFrameBuffer *fb, GPUTexture *tex, int slot
 	}
 
 	if (GPU_texture_depth(tex))
-		attachment = GL_DEPTH_ATTACHMENT_EXT;
+		attachment = GL_DEPTH_ATTACHMENT;
 	else
-		attachment = GL_COLOR_ATTACHMENT0_EXT + slot;
+		attachment = GL_COLOR_ATTACHMENT0 + slot;
 
-	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb->object);
+	glBindFramebuffer(GL_FRAMEBUFFER, fb->object);
 	GG.currentfb = fb->object;
 
 	/* Clean glError buffer. */
 	while (glGetError() != GL_NO_ERROR) {}
 
-	glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, attachment, 
+	glFramebufferTexture2D(GL_FRAMEBUFFER, attachment,
 		GPU_texture_target(tex), GPU_texture_opengl_bindcode(tex), 0);
 
 	error = glGetError();
@@ -188,21 +182,21 @@ void GPU_framebuffer_texture_detach(GPUTexture *tex)
 		return;
 
 	if (GG.currentfb != fb->object) {
-		glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb->object);
+		glBindFramebuffer(GL_FRAMEBUFFER, fb->object);
 		GG.currentfb = fb->object;
 	}
 
 	if (GPU_texture_depth(tex)) {
 		fb->depthtex = NULL;
-		attachment = GL_DEPTH_ATTACHMENT_EXT;
+		attachment = GL_DEPTH_ATTACHMENT;
 	}
 	else {
 		BLI_assert(fb->colortex[fb_attachment] == tex);
 		fb->colortex[fb_attachment] = NULL;
-		attachment = GL_COLOR_ATTACHMENT0_EXT + fb_attachment;
+		attachment = GL_COLOR_ATTACHMENT0 + fb_attachment;
 	}
 
-	glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, attachment, GPU_texture_target(tex), 0, 0);
+	glFramebufferTexture2D(GL_FRAMEBUFFER, attachment, GPU_texture_target(tex), 0, 0);
 
 	GPU_texture_framebuffer_set(tex, NULL, -1);
 }
@@ -222,7 +216,7 @@ void GPU_texture_bind_as_framebuffer(GPUTexture *tex)
 	glDisable(GL_SCISSOR_TEST);
 
 	/* bind framebuffer */
-	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb->object);
+	glBindFramebuffer(GL_FRAMEBUFFER, fb->object);
 
 	if (GPU_texture_depth(tex)) {
 		glDrawBuffer(GL_NONE);
@@ -230,8 +224,8 @@ void GPU_texture_bind_as_framebuffer(GPUTexture *tex)
 	}
 	else {
 		/* last bound prevails here, better allow explicit control here too */
-		glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT + fb_attachment);
-		glReadBuffer(GL_COLOR_ATTACHMENT0_EXT + fb_attachment);
+		glDrawBuffer(GL_COLOR_ATTACHMENT0 + fb_attachment);
+		glReadBuffer(GL_COLOR_ATTACHMENT0 + fb_attachment);
 	}
 	
 	if (GPU_texture_target(tex) == GL_TEXTURE_2D_MULTISAMPLE) {
@@ -260,7 +254,7 @@ void GPU_framebuffer_slots_bind(GPUFrameBuffer *fb, int slot)
 	
 	for (i = 0; i < 4; i++) {
 		if (fb->colortex[i]) {
-			attachments[numslots] = GL_COLOR_ATTACHMENT0_EXT + i;
+			attachments[numslots] = GL_COLOR_ATTACHMENT0 + i;
 			numslots++;
 		}
 	}
@@ -270,11 +264,11 @@ void GPU_framebuffer_slots_bind(GPUFrameBuffer *fb, int slot)
 	glDisable(GL_SCISSOR_TEST);
 
 	/* bind framebuffer */
-	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb->object);
+	glBindFramebuffer(GL_FRAMEBUFFER, fb->object);
 
 	/* last bound prevails here, better allow explicit control here too */
 	glDrawBuffers(numslots, attachments);
-	glReadBuffer(GL_COLOR_ATTACHMENT0_EXT + slot);
+	glReadBuffer(GL_COLOR_ATTACHMENT0 + slot);
 
 	/* push matrices and set default viewport and matrix */
 	glViewport(0, 0, GPU_texture_width(fb->colortex[slot]), GPU_texture_height(fb->colortex[slot]));
@@ -301,10 +295,10 @@ void GPU_framebuffer_texture_unbind(GPUFrameBuffer *UNUSED(fb), GPUTexture *UNUS
 
 void GPU_framebuffer_bind_no_save(GPUFrameBuffer *fb, int slot)
 {
-	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb->object);
+	glBindFramebuffer(GL_FRAMEBUFFER, fb->object);
 	/* last bound prevails here, better allow explicit control here too */
-	glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT + slot);
-	glReadBuffer(GL_COLOR_ATTACHMENT0_EXT + slot);
+	glDrawBuffer(GL_COLOR_ATTACHMENT0 + slot);
+	glReadBuffer(GL_COLOR_ATTACHMENT0 + slot);
 
 	/* push matrices and set default viewport and matrix */
 	glViewport(0, 0, GPU_texture_width(fb->colortex[slot]), GPU_texture_height(fb->colortex[slot]));
@@ -321,15 +315,15 @@ bool GPU_framebuffer_check_valid(GPUFrameBuffer *fb, char err_out[256])
 {
 	GLenum status;
 	
-	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb->object);
+	glBindFramebuffer(GL_FRAMEBUFFER, fb->object);
 	GG.currentfb = fb->object;
 	
 	/* Clean glError buffer. */
 	while (glGetError() != GL_NO_ERROR) {}
 	
-	status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
+	status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
 	
-	if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
+	if (status != GL_FRAMEBUFFER_COMPLETE) {
 		GPU_framebuffer_restore();
 		GPU_print_framebuffer_error(status, err_out);
 		return false;
@@ -351,10 +345,10 @@ void GPU_framebuffer_free(GPUFrameBuffer *fb)
 	}
 
 	if (fb->object) {
-		glDeleteFramebuffersEXT(1, &fb->object);
+		glDeleteFramebuffers(1, &fb->object);
 
 		if (GG.currentfb == fb->object) {
-			glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+			glBindFramebuffer(GL_FRAMEBUFFER, 0);
 			GG.currentfb = 0;
 		}
 	}
@@ -365,7 +359,7 @@ void GPU_framebuffer_free(GPUFrameBuffer *fb)
 void GPU_framebuffer_restore(void)
 {
 	if (GG.currentfb != 0) {
-		glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+		glBindFramebuffer(GL_FRAMEBUFFER, 0);
 		GG.currentfb = 0;
 	}
 }
@@ -390,8 +384,8 @@ void GPU_framebuffer_blur(
 
 	/* We do the bind ourselves rather than using GPU_framebuffer_texture_bind() to avoid
 	 * pushing unnecessary matrices onto the OpenGL stack. */
-	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, blurfb->object);
-	glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
+	glBindFramebuffer(GL_FRAMEBUFFER, blurfb->object);
+	glDrawBuffer(GL_COLOR_ATTACHMENT0);
 	
 	/* avoid warnings from texture binding */
 	GG.currentfb = blurfb->object;
@@ -423,8 +417,8 @@ void GPU_framebuffer_blur(
 
 	/* Blurring vertically */
 
-	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb->object);
-	glDrawBuffer(GL_COLOR_ATTACHMENT0_EXT);
+	glBindFramebuffer(GL_FRAMEBUFFER, fb->object);
+	glDrawBuffer(GL_COLOR_ATTACHMENT0);
 	
 	GG.currentfb = fb->object;
 	
@@ -464,12 +458,7 @@ GPUOffScreen *GPU_offscreen_create(int width, int height, int samples, char err_
 	}
 
 	if (samples) {
-		if (!GLEW_EXT_framebuffer_multisample ||
-		    !GLEW_ARB_texture_multisample ||
-		    /* Only needed for GPU_offscreen_read_pixels.
-		     * We could add an arg if we intend to use multi-sample
-		     * offscreen buffers w/o reading their pixels */
-		    !GLEW_EXT_framebuffer_blit ||
+		if (!GLEW_ARB_texture_multisample ||
 		    /* This is required when blitting from a multi-sampled buffers,
 		     * even though we're not scaling. */
 		    !GLEW_EXT_framebuffer_multisample_blit_scaled)
@@ -569,37 +558,37 @@ void GPU_offscreen_read_pixels(GPUOffScreen *ofs, int type, void *pixels)
 
 #ifdef USE_FBO_CTX_SWITCH
 		/* read from multi-sample buffer */
-		glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, ofs->color->fb->object);
-		glFramebufferTexture2DEXT(
-		        GL_READ_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT + ofs->color->fb_attachment,
+		glBindFramebuffer(GL_READ_FRAMEBUFFER, ofs->color->fb->object);
+		glFramebufferTexture2D(
+		        GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + ofs->color->fb_attachment,
 		        GL_TEXTURE_2D_MULTISAMPLE, ofs->color->bindcode, 0);
-		status = glCheckFramebufferStatusEXT(GL_READ_FRAMEBUFFER_EXT);
-		if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
+		status = glCheckFramebufferStatusEXT(GL_READ_FRAMEBUFFER);
+		if (status != GL_FRAMEBUFFER_COMPLETE) {
 			goto finally;
 		}
 #endif
 
 		/* write into new single-sample buffer */
-		glGenFramebuffersEXT(1, &fbo_blit);
-		glBindFramebufferEXT(GL_DRAW_FRAMEBUFFER_EXT, fbo_blit);
-		glFramebufferTexture2DEXT(
-		        GL_DRAW_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
+		glGenFramebuffers(1, &fbo_blit);
+		glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo_blit);
+		glFramebufferTexture2D(
+		        GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
 		        GL_TEXTURE_2D, tex_blit, 0);
-		status = glCheckFramebufferStatusEXT(GL_DRAW_FRAMEBUFFER_EXT);
-		if (status != GL_FRAMEBUFFER_COMPLETE_EXT) {
+		status = glCheckFramebufferStatus(GL_DRAW_FRAMEBUFFER);
+		if (status != GL_FRAMEBUFFER_COMPLETE) {
 			goto finally;
 		}
 
 		/* perform the copy */
-		glBlitFramebufferEXT(0, 0, w, h, 0, 0, w, h, GL_COLOR_BUFFER_BIT, GL_NEAREST);
+		glBlitFramebuffer(0, 0, w, h, 0, 0, w, h, GL_COLOR_BUFFER_BIT, GL_NEAREST);
 
 		/* read the results */
-		glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, fbo_blit);
+		glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo_blit);
 		glReadPixels(0, 0, w, h, GL_RGBA, type, pixels);
 
 #ifdef USE_FBO_CTX_SWITCH
 		/* restore the original frame-bufer */
-		glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, ofs->color->fb->object);
+		glBindFramebuffer(GL_FRAMEBUFFER, ofs->color->fb->object);
 #undef USE_FBO_CTX_SWITCH
 #endif
 
@@ -610,7 +599,7 @@ finally:
 			glDeleteTextures(1, &tex_blit);
 		}
 		if (fbo_blit) {
-			glDeleteFramebuffersEXT(1, &fbo_blit);
+			glDeleteFramebuffers(1, &fbo_blit);
 		}
 
 		GPU_ASSERT_NO_GL_ERRORS("Read Multi-Sample Pixels");