Basic soft shadows

1 files changed, 18 insertions, 7 deletions

diff --git a/gfx/gl/shaders/directionalLight.fs b/gfx/gl/shaders/directionalLight.fs
index 86447ec..cdf0389 100644
--- a/gfx/gl/shaders/directionalLight.fs
+++ b/gfx/gl/shaders/directionalLight.fs
@@ -17,24 +17,35 @@ uniform ivec3 lightPoint;
 uniform mat4 lightViewProjection[MAX_MAPS];
 uniform uint lightViewProjectionCount;
 
-const vec3 e1 = vec3(0, 0, 0), e2 = vec3(1, 1, 1);
+float
+getShadow(vec3 positionInLightSpace, float m, vec2 texelSize)
+{
+	float shadow = 0.0;
+	for (float x = -texelSize.x; x <= texelSize.x; x += texelSize.x) {
+		for (float y = -texelSize.y; y <= texelSize.y; y += texelSize.y) {
+			const float lightSpaceDepth = texture(shadowMap, vec3(positionInLightSpace.xy + vec2(x, y), m)).r;
+			shadow += step(positionInLightSpace.z, lightSpaceDepth + 0.001);
+		}
+	}
+	return shadow / 9.0;
+}
 
 float
-insideShadowCube(vec3 v)
+insideShadowCube(vec3 v, vec2 texelSize)
 {
-	const vec3 s = step(e1, v) - step(e2, v);
+	const vec3 s = step(vec3(texelSize, 0), v) - step(vec3(1 - texelSize, 1), v);
 	return s.x * s.y * s.z;
 }
 
 float
 isShaded(vec4 Position)
 {
+	const vec2 texelSize = 1.0 / textureSize(shadowMap, 0).xy;
 	for (uint m = 0u; m < lightViewProjectionCount; m++) {
-		const vec3 PositionInLightSpace = (lightViewProjection[m] * Position).xyz;
-		const float inside = insideShadowCube(PositionInLightSpace);
+		const vec3 positionInLightSpace = (lightViewProjection[m] * Position).xyz;
+		const float inside = insideShadowCube(positionInLightSpace, texelSize);
 		if (inside > 0) {
-			const float lightSpaceDepth = texture(shadowMap, vec3(PositionInLightSpace.xy, m)).r;
-			return step(PositionInLightSpace.z, lightSpaceDepth + 0.001);
+			return getShadow(positionInLightSpace, m, texelSize);
 		}
 	}
 	return 1;