[Bf-blender-cvs] [12fa6750f5d] blender2.8: Eevee : Add a workaround for bug with AMD RX VEGA Linux + Mesa Driver

[Clément Foucault]

Commit: 12fa6750f5d360ead02ca5820da34c08b0200bb0
Author: Clément Foucault
Date:   Tue Oct 10 17:18:29 2017 +0200
Branches: blender2.8
https://developer.blender.org/rB12fa6750f5d360ead02ca5820da34c08b0200bb0

Eevee : Add a workaround for bug with AMD RX VEGA Linux + Mesa Driver

This bug (explained here https://github.com/dfelinto/opengl-sandbox/blob/downsample/README.md) is breaking eevee beyond the point it's workable.

This patch workaround the issue by making sure every fbo have mipmaps that are strictly greater than 16px. This break the bloom visuals a bit but only for this setup.

===================================================================

M	source/blender/draw/engines/eevee/eevee_effects.c
M	source/blender/gpu/GPU_extensions.h
M	source/blender/gpu/intern/gpu_extensions.c
M	source/blender/gpu/intern/gpu_framebuffer.c

===================================================================

diff --git a/source/blender/draw/engines/eevee/eevee_effects.c b/source/blender/draw/engines/eevee/eevee_effects.c
index 8df2c56faeb..95da6e6c8f4 100644
--- a/source/blender/draw/engines/eevee/eevee_effects.c
+++ b/source/blender/draw/engines/eevee/eevee_effects.c
@@ -46,8 +46,9 @@
 #include "BLI_rand.h"
 
 #include "eevee_private.h"
-#include "GPU_texture.h"
+#include "GPU_extensions.h"
 #include "GPU_framebuffer.h"
+#include "GPU_texture.h"
 
 #define SHADER_DEFINES \
 	"#define EEVEE_ENGINE\n" \
@@ -403,8 +404,15 @@ void EEVEE_effects_init(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata)
 		copy_v2_v2_int(texsize, blitsize);
 		for (int i = 0; i < effects->bloom_iteration_ct; ++i) {
 			texsize[0] /= 2; texsize[1] /= 2;
-			texsize[0] = MAX2(texsize[0], 2);
-			texsize[1] = MAX2(texsize[1], 2);
+
+			if (GPU_type_matches(GPU_DEVICE_AMD_VEGA, GPU_OS_UNIX, GPU_DRIVER_OPENSOURCE)) {
+				texsize[0] = MAX2(texsize[0], 17);
+				texsize[1] = MAX2(texsize[1], 17);
+			}
+			else {
+				texsize[0] = MAX2(texsize[0], 2);
+				texsize[1] = MAX2(texsize[1], 2);
+			}
 
 			effects->downsamp_texel_size[i][0] = 1.0f / (float)texsize[0];
 			effects->downsamp_texel_size[i][1] = 1.0f / (float)texsize[1];
@@ -419,8 +427,15 @@ void EEVEE_effects_init(EEVEE_SceneLayerData *sldata, EEVEE_Data *vedata)
 		copy_v2_v2_int(texsize, blitsize);
 		for (int i = 0; i < effects->bloom_iteration_ct - 1; ++i) {
 			texsize[0] /= 2; texsize[1] /= 2;
-			texsize[0] = MAX2(texsize[0], 2);
-			texsize[1] = MAX2(texsize[1], 2);
+
+			if (GPU_type_matches(GPU_DEVICE_AMD_VEGA, GPU_OS_UNIX, GPU_DRIVER_OPENSOURCE)) {
+				texsize[0] = MAX2(texsize[0], 17);
+				texsize[1] = MAX2(texsize[1], 17);
+			}
+			else {
+				texsize[0] = MAX2(texsize[0], 2);
+				texsize[1] = MAX2(texsize[1], 2);
+			}
 
 			DRWFboTexture tex_bloom = {&txl->bloom_upsample[i], DRW_TEX_RGB_11_11_10, DRW_TEX_FILTER};
 			DRW_framebuffer_init(&fbl->bloom_accum_fb[i], &draw_engine_eevee_type,
diff --git a/source/blender/gpu/GPU_extensions.h b/source/blender/gpu/GPU_extensions.h
index d36b0ea15be..d860431b04f 100644
--- a/source/blender/gpu/GPU_extensions.h
+++ b/source/blender/gpu/GPU_extensions.h
@@ -64,6 +64,7 @@ typedef enum GPUDeviceType {
 	GPU_DEVICE_INTEL =      (1 << 2),
 	GPU_DEVICE_SOFTWARE =   (1 << 3),
 	GPU_DEVICE_UNKNOWN =    (1 << 4),
+	GPU_DEVICE_AMD_VEGA =   (1 << 5),
 	GPU_DEVICE_ANY =        (0xff)
 } GPUDeviceType;
 
diff --git a/source/blender/gpu/intern/gpu_extensions.c b/source/blender/gpu/intern/gpu_extensions.c
index 6bf330179d3..1159603f721 100644
--- a/source/blender/gpu/intern/gpu_extensions.c
+++ b/source/blender/gpu/intern/gpu_extensions.c
@@ -178,6 +178,13 @@ void gpu_extensions_init(void)
 		GG.device = GPU_DEVICE_ATI;
 		GG.driver = GPU_DRIVER_OFFICIAL;
 	}
+	/* XXX : TODO : Remove this once this sampling mipmap problem is gone.
+	 * https://github.com/dfelinto/opengl-sandbox/blob/downsample/README.md */
+	else if (strstr(renderer, "AMD VEGA") ||
+	         strstr(vendor, "X.Org")) {
+		GG.device = GPU_DEVICE_AMD_VEGA;
+		GG.driver = GPU_DRIVER_OPENSOURCE;
+	}
 	else if (strstr(vendor, "NVIDIA")) {
 		GG.device = GPU_DEVICE_NVIDIA;
 		GG.driver = GPU_DRIVER_OFFICIAL;
diff --git a/source/blender/gpu/intern/gpu_framebuffer.c b/source/blender/gpu/intern/gpu_framebuffer.c
index 6b19cea464b..1d157ecb14c 100644
--- a/source/blender/gpu/intern/gpu_framebuffer.c
+++ b/source/blender/gpu/intern/gpu_framebuffer.c
@@ -34,6 +34,7 @@
 
 #include "GPU_batch.h"
 #include "GPU_draw.h"
+#include "GPU_extensions.h"
 #include "GPU_framebuffer.h"
 #include "GPU_matrix.h"
 #include "GPU_shader.h"
@@ -573,7 +574,20 @@ void GPU_framebuffer_recursive_downsample(
 		glReadBuffer(GL_COLOR_ATTACHMENT0);
 	}
 
-	for (i = 1; i < num_iter + 1 && (current_dim[0] > 4 && current_dim[1] > 4); i++) {
+	for (i = 1; i < num_iter + 1; i++) {
+
+		if (GPU_type_matches(GPU_DEVICE_AMD_VEGA, GPU_OS_UNIX, GPU_DRIVER_OPENSOURCE)) {
+			/* NOTE : here 16 is because of a bug on AMD Vega GPU + non-pro drivers, that prevents us
+			 * from sampling mipmaps that are smaller or equal to 16px. (9) */
+			if (current_dim[0] / 2 > 16 && current_dim[1] / 2 > 16) {
+				break;
+			}
+		}
+		else {
+			if (current_dim[0] / 2 > 1 && current_dim[1] / 2 > 1) {
+				break;
+			}
+		}
 
 		/* calculate next viewport size */
 		current_dim[0] /= 2;