First pass at PBO

[clouds.git] / billboardfrag.glsl

diff --git a/billboardfrag.glsl b/billboardfrag.glsl
index 2349e4dfef4610558042a9f6b8315e1ac217800a..39fd71d135d1d36fb9fe820fc9eef3a79082e9cc 100644 (file)
--- a/billboardfrag.glsl
+++ b/billboardfrag.glsl
@@ -4,9 +4,20 @@ uniform sampler2D tex;
 in vec2 texCoord;
 out vec4 FragColor;
 uniform bool modulate;
+uniform bool debug;
+uniform bool debugColor;
+uniform float debugVal;
 void main() {
+  if (debugColor) {
+    FragColor = color;
+    return;
+  }
+  if (debug) {
+    FragColor = mix(vec4(1, 1, 1, 0), vec4(1, 0, 0, 1), debugVal);
+    return;
+  }
        // Cf = color from fragment, Ct = color from texture
-       // Cc = color from texture environment(?) assume to be 0?
+       // Cc = color from texture environment -- not set, defaults to (0,0,0,0)
        // Af = alpha from fragment, At = alpha from texture
        // C = output color, A = output alpha
        float f = texture(tex, texCoord).r;
@@ -14,8 +25,11 @@ void main() {
                // GL_MODULATE: C
                // C = Cf * Ct
                // A = Af * At                          
-               FragColor = color * f;
+               FragColor = color * (f + 0.03); // the +0.03 is a hack to get lighter clouds!
        } else {
+        // "That is, the colors in the frame buffer are multiplied by the
+        // attenuation ratio of the billboard texture and then the colors in
+        // the texture are added"
                // GL_BLEND:
                // C = Cf * (1-Ct) + Cc * Ct
                // A = Af * At