Eevee: Initial implementation of exponential shadowmaps

Also fixes the rendering of depth.

6 files changed, 38 insertions, 20 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_lights.c b/source/blender/draw/engines/eevee/eevee_lights.c
index 7adc2696746..afc60dc3a44 100644
--- a/source/blender/draw/engines/eevee/eevee_lights.c
+++ b/source/blender/draw/engines/eevee/eevee_lights.c
@@ -200,7 +200,7 @@ void EEVEE_lights_cache_finish(EEVEE_StorageList *stl, EEVEE_TextureList *txl, E
 	if (!txl->shadow_depth_cube_target) {
 		/* Render Cubemap */
 		txl->shadow_depth_cube_target = DRW_texture_create_cube(512, DRW_TEX_DEPTH_24, 0, NULL);
-		txl->shadow_color_cube_target = DRW_texture_create_cube(512, DRW_TEX_R_32, 0, NULL);
+		txl->shadow_color_cube_target = DRW_texture_create_cube(512, DRW_TEX_R_32, DRW_TEX_FILTER, NULL);
 		if (fbl->shadow_cube_fb) {
 			DRW_framebuffer_texture_attach(fbl->shadow_cube_fb, txl->shadow_depth_cube_target, 0, 0);
 			DRW_framebuffer_texture_attach(fbl->shadow_cube_fb, txl->shadow_color_cube_target, 0, 0);
@@ -235,7 +235,7 @@ void EEVEE_lights_cache_finish(EEVEE_StorageList *stl, EEVEE_TextureList *txl, E
 
 	DRWFboTexture tex_cube_target[2] = {
 	        {&txl->shadow_depth_cube_target, DRW_TEX_DEPTH_24, 0},
-	        {&txl->shadow_color_cube_target, DRW_TEX_R_32, 0}};
+	        {&txl->shadow_color_cube_target, DRW_TEX_R_32, DRW_TEX_FILTER}};
 	DRW_framebuffer_init(&fbl->shadow_cube_target_fb, &draw_engine_eevee_type, 512, 512, tex_cube_target, 2);
 
 	DRWFboTexture tex_cube = {&txl->shadow_depth_cube_pool, DRW_TEX_R_32, DRW_TEX_FILTER};
diff --git a/source/blender/draw/engines/eevee/shaders/lit_surface_frag.glsl b/source/blender/draw/engines/eevee/shaders/lit_surface_frag.glsl
index 1c124c06744..ecfc670c0d6 100644
--- a/source/blender/draw/engines/eevee/shaders/lit_surface_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/lit_surface_frag.glsl
@@ -129,7 +129,7 @@ float light_visibility(LightData ld, ShadingData sd)
 
 		vis *= texture(shadowCascades, vec4(shpos.xy, shid * float(MAX_CASCADE_NUM) + cascade, shpos.z));
 	}
-	else {
+	else if (ld.l_shadowid >= 0.0) {
 		/* Shadow Cube */
 		float shid = ld.l_shadowid;
 		ShadowCubeData scd = shadows_cube_data[int(shid)];
@@ -150,9 +150,12 @@ float light_visibility(LightData ld, ShadingData sd)
 		vec2 uvs = cubevec.xy * (0.5) + 0.5;
 		uvs = uvs * (1.0 - 2.0 * texelSize) + 1.0 * texelSize; /* edge filtering fix */
 
-		float sh_test = step(0, texture(shadowCubes, vec3(uvs, shid)).r - dist);
+		float z = texture(shadowCubes, vec3(uvs, shid)).r;
+
+		float esm_test = min(1.0, exp(-5.0 * dist) * z);
+		float sh_test = step(0, z - dist);
 
-		vis *= sh_test;
+		vis *= esm_test;
 	}
 
 	return vis;
diff --git a/source/blender/draw/engines/eevee/shaders/shadow_frag.glsl b/source/blender/draw/engines/eevee/shaders/shadow_frag.glsl
index 0b7356d812b..7a8b06e3430 100644
--- a/source/blender/draw/engines/eevee/shaders/shadow_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/shadow_frag.glsl
@@ -1,8 +1,15 @@
 
-in float linearDistance;
+layout(std140) uniform shadow_render_block {
+	mat4 ShadowMatrix[6];
+	vec4 lampPosition;
+	int layer;
+};
+
+in vec3 worldPosition;
 
 out vec4 FragColor;
 
 void main() {
-	FragColor = vec4(linearDistance, 0.0, 0.0, 1.0);
+	float dist = distance(lampPosition.xyz, worldPosition.xyz);
+	FragColor = vec4(exp(5.0 * dist), 0.0, 0.0, 1.0);
 }
diff --git a/source/blender/draw/engines/eevee/shaders/shadow_geom.glsl b/source/blender/draw/engines/eevee/shaders/shadow_geom.glsl
index c4738de2f31..4bd2999787b 100644
--- a/source/blender/draw/engines/eevee/shaders/shadow_geom.glsl
+++ b/source/blender/draw/engines/eevee/shaders/shadow_geom.glsl
@@ -9,10 +9,9 @@ layout(triangles) in;
 layout(triangle_strip, max_vertices=3) out;
 
 in vec4 vPos[];
-in float lDist[];
 flat in int face[];
 
-out float linearDistance;
+out vec3 worldPosition;
 
 void main() {
 	int f = face[0];
@@ -20,7 +19,7 @@ void main() {
 
 	for (int v = 0; v < 3; ++v) {
 		gl_Position = ShadowMatrix[f] * vPos[v];
-		linearDistance = lDist[v];
+		worldPosition = vPos[v].xyz;
 		EmitVertex();
 	}
 
diff --git a/source/blender/draw/engines/eevee/shaders/shadow_store_frag.glsl b/source/blender/draw/engines/eevee/shaders/shadow_store_frag.glsl
index 08453080ed2..67bee97fade 100644
--- a/source/blender/draw/engines/eevee/shaders/shadow_store_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/shadow_store_frag.glsl
@@ -17,6 +17,13 @@ vec3 octahedral_to_cubemap_proj(vec2 co)
 	return v;
 }
 
+void make_orthonormal_basis(vec3 N, out vec3 T, out vec3 B)
+{
+	vec3 UpVector = abs(N.z) < 0.99999 ? vec3(0.0,0.0,1.0) : vec3(1.0,0.0,0.0);
+	T = normalize( cross(UpVector, N) );
+	B = cross(N, T);
+}
+
 void main() {
 	const vec2 texelSize = vec2(1.0 / 512.0);
 
@@ -42,6 +49,16 @@ void main() {
 	/* get cubemap vector */
 	vec3 cubevec = octahedral_to_cubemap_proj(uvs.xy);
 
-	/* get cubemap vector */
-	FragColor = texture(shadowCube, cubevec).rrrr;
+	vec3 T, B;
+	make_orthonormal_basis(cubevec, T, B);
+
+	vec2 offsetvec = texelSize.xy * vec2(-1.0, 1.0); /* Totally arbitrary */
+
+	/* get cubemap shadow value */
+	FragColor  = texture(shadowCube, cubevec + offsetvec.x * T + offsetvec.x * B).rrrr;
+	FragColor += texture(shadowCube, cubevec + offsetvec.x * T + offsetvec.y * B).rrrr;
+	FragColor += texture(shadowCube, cubevec + offsetvec.y * T + offsetvec.x * B).rrrr;
+	FragColor += texture(shadowCube, cubevec + offsetvec.y * T + offsetvec.y * B).rrrr;
+
+	FragColor /= 4.0;
 }
\ No newline at end of file
diff --git a/source/blender/draw/engines/eevee/shaders/shadow_vert.glsl b/source/blender/draw/engines/eevee/shaders/shadow_vert.glsl
index 323cf4d2a99..288098ba771 100644
--- a/source/blender/draw/engines/eevee/shaders/shadow_vert.glsl
+++ b/source/blender/draw/engines/eevee/shaders/shadow_vert.glsl
@@ -1,21 +1,13 @@
 
-layout(std140) uniform shadow_render_block {
-	mat4 ShadowMatrix[6];
-	vec4 lampPosition;
-	int layer;
-};
-
 uniform mat4 ShadowModelMatrix;
 
 in vec3 pos;
 
 out vec4 vPos;
-out float lDist;
 
 flat out int face;
 
 void main() {
 	vPos = ShadowModelMatrix * vec4(pos, 1.0);
-	lDist = distance(lampPosition.xyz, vPos.xyz);
 	face = gl_InstanceID;
 }
\ No newline at end of file