Workbench: Fix workbench broken on some config due to usuned fb slot

This seems to be a driver bug. Only windows + Radeon HD 7500M seems
to be affected. Fix can be extended to more config if necessary.

3 files changed, 21 insertions, 2 deletions

diff --git a/source/blender/draw/engines/workbench/workbench_deferred.c b/source/blender/draw/engines/workbench/workbench_deferred.c
index a07c9f37ac9..1e401b278be 100644
--- a/source/blender/draw/engines/workbench/workbench_deferred.c
+++ b/source/blender/draw/engines/workbench/workbench_deferred.c
@@ -403,6 +403,7 @@ void workbench_deferred_engine_init(WORKBENCH_Data *vedata)
 		const int size[2] = {(int)viewport_size[0], (int)viewport_size[1]};
 		const GPUTextureFormat nor_tex_format = NORMAL_ENCODING_ENABLED() ? GPU_RG16 : GPU_RGBA32F;
 		const GPUTextureFormat comp_tex_format = DRW_state_is_image_render() ? GPU_RGBA16F : GPU_R11F_G11F_B10F;
+		const GPUTextureFormat id_tex_format = OBJECT_ID_PASS_ENABLED(wpd) ? GPU_R32UI : GPU_R8;
 
 		e_data.object_id_tx = NULL;
 		e_data.color_buffer_tx = NULL;
@@ -412,8 +413,9 @@ void workbench_deferred_engine_init(WORKBENCH_Data *vedata)
 
 		e_data.color_buffer_tx = DRW_texture_pool_query_2D(size[0], size[1], GPU_RGBA8, &draw_engine_workbench_solid);
 		e_data.composite_buffer_tx = DRW_texture_pool_query_2D(size[0], size[1], comp_tex_format, &draw_engine_workbench_solid);
-		if (OBJECT_ID_PASS_ENABLED(wpd)) {
-			e_data.object_id_tx = DRW_texture_pool_query_2D(size[0], size[1], GPU_R32UI, &draw_engine_workbench_solid);
+
+		if (OBJECT_ID_PASS_ENABLED(wpd) || GPU_unused_fb_slot_workaround()) {
+			e_data.object_id_tx = DRW_texture_pool_query_2D(size[0], size[1], id_tex_format, &draw_engine_workbench_solid);
 		}
 		if (NORMAL_VIEWPORT_PASS_ENABLED(wpd)) {
 			e_data.normal_buffer_tx = DRW_texture_pool_query_2D(size[0], size[1], nor_tex_format, &draw_engine_workbench_solid);
diff --git a/source/blender/gpu/GPU_extensions.h b/source/blender/gpu/GPU_extensions.h
index 12a640747da..22eb917f0bd 100644
--- a/source/blender/gpu/GPU_extensions.h
+++ b/source/blender/gpu/GPU_extensions.h
@@ -54,6 +54,7 @@ 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);
+bool GPU_unused_fb_slot_workaround(void);
 
 bool GPU_mem_stats_supported(void);
 void GPU_mem_stats_get(int *totalmem, int *freemem);
diff --git a/source/blender/gpu/intern/gpu_extensions.c b/source/blender/gpu/intern/gpu_extensions.c
index 99f770b4d03..92d91bd440d 100644
--- a/source/blender/gpu/intern/gpu_extensions.c
+++ b/source/blender/gpu/intern/gpu_extensions.c
@@ -95,6 +95,9 @@ static struct GPUGlobal {
 	 * GPU_DEPTH32F_STENCIL8. Then Blitting depth will work but blitting stencil will
 	 * still be broken. */
 	bool depth_blitting_workaround;
+	/* Crappy driver don't know how to map framebuffer slot to output vars...
+	 * We need to have no "holes" in the output buffer slots. */
+	bool unused_fb_slot_workaround;
 } GG = {1, 0};
 
 
@@ -211,6 +214,11 @@ bool GPU_depth_blitting_workaround(void)
 	return GG.depth_blitting_workaround;
 }
 
+bool GPU_unused_fb_slot_workaround(void)
+{
+	return GG.unused_fb_slot_workaround;
+}
+
 void gpu_extensions_init(void)
 {
 	/* during 2.8 development each platform has its own OpenGL minimum requirements
@@ -262,6 +270,14 @@ void gpu_extensions_init(void)
 		GG.device = GPU_DEVICE_ATI;
 		GG.driver = GPU_DRIVER_OFFICIAL;
 
+#ifdef _WIN32
+		if (strstr(vendor, "Radeon HD 7500M") ||
+		    strstr(vendor, "Radeon HD 7570M"))
+		{
+			GG.unused_fb_slot_workaround = true;
+		}
+#endif
+
 #if defined(__APPLE__)
 		if (strstr(renderer, "AMD Radeon Pro") ||
 		    strstr(renderer, "AMD Radeon R9") ||