[Bf-blender-cvs] [b858b44f2e1] blender2.8: Eevee: Fix and opimize MinMaxZ generation.

[Clément Foucault]

Commit: b858b44f2e151a8ccf417a0207d039a07f449d29
Author: Clément Foucault
Date:   Sat Aug 12 16:13:08 2017 +0200
Branches: blender2.8
https://developer.blender.org/rBb858b44f2e151a8ccf417a0207d039a07f449d29

Eevee: Fix and opimize MinMaxZ generation.

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

M	source/blender/draw/engines/eevee/eevee_effects.c
M	source/blender/draw/engines/eevee/eevee_engine.c
M	source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl

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

diff --git a/source/blender/draw/engines/eevee/eevee_effects.c b/source/blender/draw/engines/eevee/eevee_effects.c
index bf45227d793..2922e4622ad 100644
--- a/source/blender/draw/engines/eevee/eevee_effects.c
+++ b/source/blender/draw/engines/eevee/eevee_effects.c
@@ -992,13 +992,13 @@ void EEVEE_create_minmax_buffer(EEVEE_Data *vedata, GPUTexture *depth_src, int l
 	EEVEE_TextureList *txl = vedata->txl;
 
 	e_data.depth_src = depth_src;
+	e_data.depth_src_layer = layer;
 
 	DRW_stats_group_start("Min buffer");
 	/* Copy depth buffer to min texture top level */
 	DRW_framebuffer_texture_attach(fbl->downsample_fb, stl->g_data->minzbuffer, 0, 0);
 	DRW_framebuffer_bind(fbl->downsample_fb);
 	if (layer >= 0) {
-		e_data.depth_src_layer = layer;
 		DRW_draw_pass(psl->minz_downdepth_layer_ps);
 	}
 	else {
@@ -1015,7 +1015,6 @@ void EEVEE_create_minmax_buffer(EEVEE_Data *vedata, GPUTexture *depth_src, int l
 	DRW_framebuffer_texture_attach(fbl->downsample_fb, txl->maxzbuffer, 0, 0);
 	DRW_framebuffer_bind(fbl->downsample_fb);
 	if (layer >= 0) {
-		e_data.depth_src_layer = layer;
 		DRW_draw_pass(psl->maxz_downdepth_layer_ps);
 	}
 	else {
diff --git a/source/blender/draw/engines/eevee/eevee_engine.c b/source/blender/draw/engines/eevee/eevee_engine.c
index d2fcc066e9c..14791952560 100644
--- a/source/blender/draw/engines/eevee/eevee_engine.c
+++ b/source/blender/draw/engines/eevee/eevee_engine.c
@@ -171,8 +171,6 @@ static void EEVEE_draw_scene(void *vedata)
 		DRW_draw_pass(psl->depth_pass_cull);
 		DRW_stats_group_end();
 
-		DRW_draw_pass(psl->background_pass);
-
 		/* Create minmax texture */
 		DRW_stats_group_start("Main MinMax buffer");
 		EEVEE_create_minmax_buffer(vedata, dtxl->depth, -1);
@@ -183,6 +181,7 @@ static void EEVEE_draw_scene(void *vedata)
 
 		/* Shading pass */
 		DRW_stats_group_start("Shading");
+		DRW_draw_pass(psl->background_pass);
 		EEVEE_draw_default_passes(psl);
 		DRW_draw_pass(psl->material_pass);
 		DRW_stats_group_end();
diff --git a/source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl b/source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl
index 3d580d0ce39..71e249e1599 100644
--- a/source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/effect_minmaxz_frag.glsl
@@ -11,23 +11,17 @@ uniform int depthLayer;
 uniform sampler2D depthBuffer;
 #endif
 
-float sampleLowerMip(ivec2 texel)
-{
 #ifdef LAYERED
-	return texelFetch(depthBuffer, ivec3(texel, depthLayer), 0).r;
+#define sampleLowerMip(t) texelFetch(depthBuffer, ivec3(t, depthLayer), 0).r
 #else
-	return texelFetch(depthBuffer, texel, 0).r;
+#define sampleLowerMip(t) texelFetch(depthBuffer, t, 0).r
 #endif
-}
 
-void minmax(inout float out_val, float in_val)
-{
 #ifdef MIN_PASS
-	out_val = min(out_val, in_val);
+#define minmax(a, b) min(a, b)
 #else /* MAX_PASS */
-	out_val = max(out_val, in_val);
+#define minmax(a, b) max(a, b)
 #endif
-}
 
 void main()
 {
@@ -40,23 +34,30 @@ void main()
 
 	float val = sampleLowerMip(texelPos);
 #ifndef COPY_DEPTH
-	minmax(val, sampleLowerMip(texelPos + ivec2(1, 0)));
-	minmax(val, sampleLowerMip(texelPos + ivec2(1, 1)));
-	minmax(val, sampleLowerMip(texelPos + ivec2(0, 1)));
+	float val2 = sampleLowerMip(texelPos + ivec2(1, 0));
+	float val3 = sampleLowerMip(texelPos + ivec2(1, 1));
+	float val4 = sampleLowerMip(texelPos + ivec2(0, 1));
+	val = minmax(val, val2);
+	val = minmax(val, val3);
+	val = minmax(val, val4);
 
 	/* if we are reducing an odd-width texture then fetch the edge texels */
-	if (((mipsize.x & 1) != 0) && (int(gl_FragCoord.x) == mipsize.x-3)) {
+	if (((mipsize.x & 1) != 0) && (int(gl_FragCoord.x)*2 == mipsize.x-3)) {
 		/* if both edges are odd, fetch the top-left corner texel */
-		if (((mipsize.y & 1) != 0) && (int(gl_FragCoord.y) == mipsize.y-3)) {
-			minmax(val, sampleLowerMip(texelPos + ivec2(-1, -1)));
+		if (((mipsize.y & 1) != 0) && (int(gl_FragCoord.y)*2 == mipsize.y-3)) {
+			val = minmax(val, sampleLowerMip(texelPos + ivec2(2, 2)));
 		}
-		minmax(val, sampleLowerMip(texelPos + ivec2(0, -1)));
-		minmax(val, sampleLowerMip(texelPos + ivec2(1, -1)));
+		float val2 = sampleLowerMip(texelPos + ivec2(2, 0));
+		float val3 = sampleLowerMip(texelPos + ivec2(2, 1));
+		val = minmax(val, val2);
+		val = minmax(val, val3);
 	}
 	/* if we are reducing an odd-height texture then fetch the edge texels */
-	else if (((mipsize.y & 1) != 0) && (int(gl_FragCoord.y) == mipsize.y-3)) {
-		minmax(val, sampleLowerMip(texelPos + ivec2(0, -1)));
-		minmax(val, sampleLowerMip(texelPos + ivec2(1, -1)));
+	if (((mipsize.y & 1) != 0) && (int(gl_FragCoord.y)*2 == mipsize.y-3)) {
+		float val2 = sampleLowerMip(texelPos + ivec2(0, 2));
+		float val3 = sampleLowerMip(texelPos + ivec2(1, 2));
+		val = minmax(val, val2);
+		val = minmax(val, val3);
 	}
 #endif