Shadow mapping implementation draft

Does not work yet

Change-Id: Ic08c6b12fa5d5aa4f76ddef82fa81eab6982dd69
Change-Id: Ic08c6b12fa5d5aa4f76ddef82fa81eab6982dd69
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@digia.com>

1 files changed, 65 insertions, 0 deletions

diff --git a/src/datavis3d/engine/shaders/fragmentShadow b/src/datavis3d/engine/shaders/fragmentShadow
new file mode 100644
index 00000000..309c63fb
--- /dev/null
+++ b/src/datavis3d/engine/shaders/fragmentShadow
@@ -0,0 +1,65 @@
+varying highp vec4 shadowCoord;
+varying highp vec2 UV;
+varying highp vec3 position_wrld;
+varying highp vec3 normal_cmr;
+varying highp vec3 eyeDirection_cmr;
+varying highp vec3 lightDirection_cmr;
+
+uniform highp float lightStrength;
+uniform highp float ambientStrength;
+uniform highp vec3 lightPosition_wrld;
+uniform sampler2D textureSampler;
+uniform sampler2DShadow shadowMap;
+
+//float random(vec3 seed, int i){
+//    vec4 seed4 = vec4(seed,i);
+//    float dot_product = dot(seed4, vec4(12.9898, 78.233, 45.164, 94.673));
+//    return fract(sin(dot_product) * 43758.5453);
+//}
+
+void main() {
+    highp vec3 materialDiffuseColor = texture2D(textureSampler, UV).rgb;
+    highp vec3 materialAmbientColor = vec3(ambientStrength, ambientStrength, ambientStrength) * materialDiffuseColor;
+    highp vec3 materialSpecularColor = vec3(1.0, 1.0, 1.0);
+
+    highp vec3 n = normalize(normal_cmr);
+    highp vec3 l = normalize(lightDirection_cmr);
+    highp float cosTheta = dot(n, l);
+    if (cosTheta < 0.0) { cosTheta = 0.0; }
+    if (cosTheta > 1.0) { cosTheta = 1.0; }
+
+    highp vec3 E = normalize(eyeDirection_cmr);
+    highp vec3 R = reflect(-l, n);
+    highp float cosAlpha = dot(E, R);
+    if (cosAlpha < 0.0) { cosAlpha = 0.0; }
+    if (cosAlpha > 1.0) { cosAlpha = 1.0; }
+
+    highp float visibility = 1.0;
+    highp float bias = 0.005;
+    //highp bias = 0.005 * tan(acos(cosTheta));
+    //if (bias < 0.0) { bias = 0.0; }
+    //if (bias > 0.01) { bias = 0.01; }
+
+    //for (int i = 0; i < 4; i++) {
+        // use either :
+        //  - Always the same samples.
+        //    Gives a fixed pattern in the shadow, but no noise
+        //int index = i;
+        //  - A random sample, based on the pixel's screen location.
+        //    No banding, but the shadow moves with the camera, which looks weird.
+        // int index = int(16.0*random(gl_FragCoord.xyy, i))%16;
+        //  - A random sample, based on the pixel's position in world space.
+        //    The position is rounded to the millimeter to avoid too much aliasing
+        // int index = int(16.0*random(floor(Position_worldspace.xyz*1000.0), i))%16;
+
+        // being fully in the shadow will eat up 4*0.2 = 0.8
+        // 0.2 potentially remain, which is quite dark.
+        visibility -= 0.8 * (1.0 - shadow2D(shadowMap, vec3(shadowCoord.xy, (shadowCoord.z - bias) / shadowCoord.w)).r);
+    //}
+
+    gl_FragColor.rgb =
+        materialAmbientColor +
+        visibility * materialDiffuseColor * lightStrength * cosTheta +
+        visibility * materialSpecularColor * lightStrength * (cosAlpha * cosAlpha * cosAlpha * cosAlpha * cosAlpha);
+    gl_FragColor.a = 1.0;
+}