Generate and use a shadow map

Generated when the directional light is specified in the environment call, passed to the directional
light shader pass to conditionally illuminate each pixel.

1 files changed, 9 insertions, 0 deletions

diff --git a/gfx/gl/shaders/directionalLight.fs b/gfx/gl/shaders/directionalLight.fs
index 7562f96..5350bf3 100644
--- a/gfx/gl/shaders/directionalLight.fs
+++ b/gfx/gl/shaders/directionalLight.fs
@@ -5,14 +5,23 @@ out vec3 FragColor;
 
 in vec2 TexCoords;
 
+layout(binding = 0) uniform sampler2D gPosition;
 layout(binding = 1) uniform sampler2D gNormal;
+layout(binding = 2) uniform sampler2D shadowMap;
 
 uniform vec3 lightDirection;
 uniform vec3 lightColour;
+uniform mat4 lightViewProjection;
 
 void
 main()
 {
+	const vec3 Position = texture(gPosition, TexCoords).xyz;
+	const vec4 PositionInLightSpace = (lightViewProjection * vec4(Position, 1)) * 0.5 + 0.5;
+	const float lightSpaceDepth = texture(shadowMap, PositionInLightSpace.xy).r;
+	if (lightSpaceDepth < PositionInLightSpace.z) {
+		discard;
+	}
 	const vec3 Normal = texture(gNormal, TexCoords).rgb;
 	FragColor = dot(-lightDirection, Normal) * lightColour;
 }