[Shaders] Discarding fragments with an alpha value too low

- This (finally) effectively handles opacity masking
Razakhel · May 23, 2024 · bc9db43 · bc9db43
1 parent 2212d16
commit bc9db43
Show file tree

Hide file tree

Showing 3 changed files with 25 additions and 7 deletions.
diff --git a/shaders/blinn-phong.frag b/shaders/blinn-phong.frag
@@ -50,7 +50,14 @@ layout(location = 1) out vec3 fragNormal;
 layout(location = 2) out vec4 fragSpecular;
 
 void main() {
-  vec3 color      = texture(uniMaterial.baseColorMap, vertMeshInfo.vertTexcoords).rgb * uniMaterial.baseColor;
+  vec4 baseColor = texture(uniMaterial.baseColorMap, vertMeshInfo.vertTexcoords).rgba;
+  float opacity  = texture(uniMaterial.opacityMap, vertMeshInfo.vertTexcoords).r;
+  float alpha    = min(baseColor.a, opacity) * uniMaterial.opacity;
+
+  if (alpha < 0.1)
+      discard;
+
+  vec3 color      = baseColor.rgb * uniMaterial.baseColor;
   vec3 specFactor = texture(uniMaterial.specularMap, vertMeshInfo.vertTexcoords).rgb * uniMaterial.specular;
   vec3 normal     = vertMeshInfo.vertTBNMatrix[2];
   vec3 viewDir    = normalize(uniCameraPos - vertMeshInfo.vertPosition);
@@ -87,7 +94,7 @@ void main() {
   vec3 ambient  = color * 0.05;
   vec3 emissive = texture(uniMaterial.emissiveMap, vertMeshInfo.vertTexcoords).rgb * uniMaterial.emissive;
 
-  fragColor    = vec4(ambient + diffuse + specular + emissive, 1.0);
+  fragColor    = vec4(ambient + diffuse + specular + emissive, alpha);
   fragNormal   = normal * 0.5 + 0.5;
   fragSpecular = vec4(specFactor, 1.0 - max(specFactor.x, max(specFactor.y, specFactor.z)));
 }
diff --git a/shaders/cook-torrance.frag b/shaders/cook-torrance.frag
@@ -91,8 +91,12 @@ float computeGeometry(vec3 normal, vec3 viewDir, vec3 lightDir, float roughness)
 }
 
 void main() {
-  // Gamma correction for albedo (sRGB presumed)
-  vec3 albedo     = pow(texture(uniMaterial.baseColorMap, vertMeshInfo.vertTexcoords).rgb, vec3(2.2)) * uniMaterial.baseColor;
+  vec4 baseColor = texture(uniMaterial.baseColorMap, vertMeshInfo.vertTexcoords).rgba;
+
+  if (baseColor.a < 0.1)
+    discard;
+
+  vec3 albedo     = pow(baseColor.rgb, vec3(2.2)) * uniMaterial.baseColor;
   float metallic  = texture(uniMaterial.metallicMap, vertMeshInfo.vertTexcoords).r * uniMaterial.metallicFactor;
   float roughness = texture(uniMaterial.roughnessMap, vertMeshInfo.vertTexcoords).r * uniMaterial.roughnessFactor;
   float ambOcc    = texture(uniMaterial.ambientMap, vertMeshInfo.vertTexcoords).r;
@@ -156,7 +160,7 @@ void main() {
   // Gamma correction
   color = pow(color, vec3(1.0 / 2.2));
 
-  fragColor    = vec4(color, 1.0);
+  fragColor    = vec4(color, baseColor.a);
   fragNormal   = normal * 0.5 + 0.5;
   fragSpecular = vec4(baseReflectivity, roughness);
 }
diff --git a/shaders/lambert.frag b/shaders/lambert.frag
@@ -49,6 +49,13 @@ layout(location = 0) out vec4 fragColor;
 layout(location = 1) out vec3 fragNormal;
 
 void main() {
+  vec4 baseColor = texture(uniMaterial.baseColorMap, vertMeshInfo.vertTexcoords).rgba;
+  float opacity  = texture(uniMaterial.opacityMap, vertMeshInfo.vertTexcoords).r;
+  float alpha    = min(baseColor.a, opacity) * uniMaterial.opacity;
+
+  if (alpha < 0.1)
+    discard;
+
   vec3 normal = vertMeshInfo.vertTBNMatrix[2];
 
   float lightHitAngle = 0.0;
@@ -65,9 +72,9 @@ void main() {
     lightHitAngle = max(lightHitAngle, clamp(dot(lightDir, normal), 0.0, 1.0));
   }
 
-  vec3 diffuse  = lightHitAngle * texture(uniMaterial.baseColorMap, vertMeshInfo.vertTexcoords).rgb * uniMaterial.baseColor;
+  vec3 diffuse  = lightHitAngle * baseColor.rgb * uniMaterial.baseColor;
   vec3 emissive = texture(uniMaterial.emissiveMap, vertMeshInfo.vertTexcoords).rgb * uniMaterial.emissive;
 
-  fragColor  = vec4(diffuse + emissive, 1.0);
+  fragColor  = vec4(diffuse + emissive, alpha);
   fragNormal = normal;
 }