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authorDavid Thompson <dthompson2@worcester.edu>2021-08-06 08:36:25 -0400
committerDavid Thompson <dthompson2@worcester.edu>2021-08-06 08:36:25 -0400
commite326a983893117508a6e94511c2f93913cd02256 (patch)
tree125944f4955d4518c0f3cba76f998dc2451fc99d
parent8c7a0c462544ad41e696890fa912ce3ad9dbe318 (diff)
graphics: phong: Improve lighting.
-rw-r--r--chickadee/graphics/phong.scm2
-rw-r--r--data/shaders/phong-frag.glsl31
-rw-r--r--data/shaders/phong-vert.glsl2
3 files changed, 23 insertions, 12 deletions
diff --git a/chickadee/graphics/phong.scm b/chickadee/graphics/phong.scm
index f52f10b..5288075 100644
--- a/chickadee/graphics/phong.scm
+++ b/chickadee/graphics/phong.scm
@@ -107,6 +107,6 @@
#:view view-matrix
#:projection (current-projection)
#:material material
- ;; #:camera-position camera-position
+ #:camera-position camera-position
#:ambient-light-color ambient-light-color
#:lights lights))))
diff --git a/data/shaders/phong-frag.glsl b/data/shaders/phong-frag.glsl
index 84e9feb..9d8e40c 100644
--- a/data/shaders/phong-frag.glsl
+++ b/data/shaders/phong-frag.glsl
@@ -105,7 +105,7 @@ vec3 lightRadiance(Light light, vec3 direction) {
vec3 materialAmbient() {
if(material.useAmbientMap) {
- return texture(material.ambientMap, fragTex).rgb * material.ambient;
+ return texture(material.ambientMap, fragTex).rgb;
} else {
return material.ambient;
}
@@ -118,7 +118,7 @@ vec3 materialDiffuse() {
if(color.a == 0.0) {
discard;
}
- return color.rgb * material.diffuse;
+ return color.rgb;
} else {
return material.diffuse;
}
@@ -126,7 +126,7 @@ vec3 materialDiffuse() {
vec3 materialSpecular() {
if(material.useSpecularMap) {
- return texture(material.specularMap, fragTex).rgb * material.specular;
+ return texture(material.specularMap, fragTex).rgb;
} else {
return material.specular;
}
@@ -134,13 +134,27 @@ vec3 materialSpecular() {
vec3 materialNormal() {
if(material.useBumpMap) {
- return normalize(texture(material.bumpMap, fragTex).xyz * 2.0 - 1.0);
+ // Compute tangent space using fragment data rather than relying
+ // on tangent attributes. See:
+ // http://www.thetenthplanet.de/archives/1180
+ vec3 tangentNormal = normalize(texture(material.bumpMap, fragTex).xyz * 2.0 - 1.0);
+ vec3 q1 = dFdx(fragWorldPos);
+ vec3 q2 = dFdy(fragWorldPos);
+ vec2 st1 = dFdx(fragTex);
+ vec2 st2 = dFdy(fragTex);
+ vec3 N = normalize(fragNorm);
+ vec3 T = normalize(q1 * st2.t - q2 * st1.t);
+ vec3 B = -normalize(cross(N, T));
+ mat3 TBN = mat3(T, B, N);
+
+ return normalize(TBN * tangentNormal);
} else {
- return fragNorm;
+ return normalize(fragNorm);
}
}
void main() {
+ vec3 viewDir = normalize(cameraPosition - fragWorldPos);
vec3 ambientOcclusion = materialAmbient();
vec3 baseDiffuseColor = materialDiffuse();
vec3 baseSpecularColor = materialSpecular();
@@ -160,16 +174,13 @@ void main() {
float diffuseFactor = posDot(lightDir, normal);
vec3 reflectDir = reflect(-lightDir, normal);
vec3 diffuseColor = baseDiffuseColor * diffuseFactor;
- float specularFactor = 0;
- if(material.shininess > 0) {
- specularFactor = pow(posDot(lightDir, reflectDir), material.shininess);
- }
+ float specularFactor = pow(posDot(viewDir, reflectDir), material.shininess);
vec3 specularColor = baseSpecularColor * specularFactor;
color += (diffuseColor + specularColor) * radiance;
}
// Apply ambient lighting.
- vec3 ambientColor = baseDiffuseColor * ambientOcclusion * ambientLightColor.rgb;
+ vec3 ambientColor = baseDiffuseColor * ambientLightColor.rgb * ambientOcclusion;
color += ambientColor;
// Apply gamma correction and HDR tone mapping to get the final
diff --git a/data/shaders/phong-vert.glsl b/data/shaders/phong-vert.glsl
index 9b72eb3..f7fd363 100644
--- a/data/shaders/phong-vert.glsl
+++ b/data/shaders/phong-vert.glsl
@@ -30,7 +30,7 @@ uniform mat4 projection;
void main() {
fragWorldPos = vec3(model * vec4(position, 1.0));
- fragNorm = normalize(model * vec4(normal, 1.0)).xyz;
+ fragNorm = mat3(model) * normal;
fragTex = texcoord;
gl_Position = projection * view * vec4(fragWorldPos, 1.0);
}