slideshow: Add shadows to Honeycomb, using the same way as Vortex

Change-Id: I1f8f11f900f281792b417c1efead272fe3e8432e

3 files changed, 57 insertions, 6 deletions

diff --git a/slideshow/opengl/honeycombFragmentShader.glsl b/slideshow/opengl/honeycombFragmentShader.glsl
index 7e529517915f..41b6738a804f 100644
--- a/slideshow/opengl/honeycombFragmentShader.glsl
+++ b/slideshow/opengl/honeycombFragmentShader.glsl
@@ -13,8 +13,11 @@ in vec2 texturePosition;
 in float fuzz;
 in vec2 v_center;
 in vec3 normal;
+in vec4 shadowCoordinate;
 
 uniform sampler2D slideTexture;
+uniform sampler2D colorShadowTexture;
+uniform sampler2D depthShadowTexture;
 uniform float selectedTexture;
 uniform float time;
 uniform float hexagonSize;
@@ -70,8 +73,14 @@ void main()
             fragment.rgb *= actualTime;
         }
     }
+    float visibility = 1.0;
+    const float epsilon = 0.0001;
+    if (texture2D(depthShadowTexture, shadowCoordinate.xy).r < shadowCoordinate.z - epsilon)
+        visibility *= 0.7 + 0.3 * (1.0 - texture2D(colorShadowTexture, shadowCoordinate.xy).a);
     vec4 black = vec4(0.0, 0.0, 0.0, fragment.a);
-    gl_FragColor = mix(black, fragment, light);
+    if (fragment.a < 0.001)
+        discard;
+    gl_FragColor = mix(black, fragment, visibility * light);
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/slideshow/opengl/honeycombGeometryShader.glsl b/slideshow/opengl/honeycombGeometryShader.glsl
index f1c0c7058162..5269fad45e1c 100644
--- a/slideshow/opengl/honeycombGeometryShader.glsl
+++ b/slideshow/opengl/honeycombGeometryShader.glsl
@@ -12,7 +12,9 @@
 layout(triangles) in;
 layout(triangle_strip, max_vertices=27) out;
 
-in mat4 modelViewProjectionMatrix[];
+in mat4 projectionMatrix[];
+in mat4 modelViewMatrix[];
+in mat4 shadowMatrix[];
 
 uniform float hexagonSize;
 uniform sampler2D permTexture;
@@ -21,6 +23,7 @@ out vec2 texturePosition;
 out float fuzz;
 out vec2 v_center;
 out vec3 normal;
+out vec4 shadowCoordinate;
 
 const float expandFactor = 0.0318;
 
@@ -29,10 +32,35 @@ float snoise(vec2 p)
     return texture2D(permTexture, p).r;
 }
 
+mat4 identityMatrix(void)
+{
+    return mat4(1.0, 0.0, 0.0, 0.0,
+                0.0, 1.0, 0.0, 0.0,
+                0.0, 0.0, 1.0, 0.0,
+                0.0, 0.0, 0.0, 1.0);
+}
+
+mat4 scaleMatrix(vec3 axis)
+{
+    mat4 matrix = identityMatrix();
+    matrix[0][0] = axis.x;
+    matrix[1][1] = axis.y;
+    matrix[2][2] = axis.z;
+    return matrix;
+}
+
+mat4 translationMatrix(vec3 axis)
+{
+    mat4 matrix = identityMatrix();
+    matrix[3] = vec4(axis, 1.0);
+    return matrix;
+}
+
 void emitHexagonVertex(vec3 center, vec2 translation)
 {
     vec4 pos = vec4(center + hexagonSize * expandFactor * vec3(translation, 0.0), 1.0);
-    gl_Position = modelViewProjectionMatrix[0] * pos;
+    gl_Position = projectionMatrix[0] * modelViewMatrix[0] * pos;
+    shadowCoordinate = translationMatrix(vec3(0.5, 0.5, 0.5)) * scaleMatrix(vec3(0.5, 0.5, 0.5)) * shadowMatrix[0] * modelViewMatrix[0] * pos;
     texturePosition = vec2((pos.x + 1), (1 - pos.y)) / 2;
     EmitVertex();
 }
diff --git a/slideshow/opengl/honeycombVertexShader.glsl b/slideshow/opengl/honeycombVertexShader.glsl
index d54783b82b7b..32fdecef01f9 100644
--- a/slideshow/opengl/honeycombVertexShader.glsl
+++ b/slideshow/opengl/honeycombVertexShader.glsl
@@ -21,8 +21,13 @@ uniform mat4 u_operationsTransformMatrix;
 
 uniform float time;
 uniform float selectedTexture;
+uniform float shadow;
+uniform mat4 orthoProjectionMatrix;
+uniform mat4 orthoViewMatrix;
 
-out mat4 modelViewProjectionMatrix;
+out mat4 projectionMatrix;
+out mat4 modelViewMatrix;
+out mat4 shadowMatrix;
 
 mat4 translationMatrix(vec3 axis)
 {
@@ -55,7 +60,7 @@ mat4 rotationMatrix(vec3 axis, float angle)
 
 void main( void )
 {
-    mat4 modelViewMatrix = u_modelViewMatrix * u_operationsTransformMatrix * u_sceneTransformMatrix * u_primitiveTransformMatrix;
+    mat4 nmodelViewMatrix = u_modelViewMatrix * u_operationsTransformMatrix * u_sceneTransformMatrix * u_primitiveTransformMatrix;
     mat4 transformMatrix;
 
     // TODO: use the aspect ratio of the slide instead.
@@ -76,7 +81,16 @@ void main( void )
             * rotationMatrix(vec3(0.0, 0.0, 1.0), pow(0.8 * (time - 1.0), 2.0) * M_PI)
             * invertSlideScaleMatrix;
     }
-    modelViewProjectionMatrix = u_projectionMatrix * modelViewMatrix * transformMatrix;
+
+    if (shadow < 0.5) {
+        projectionMatrix = u_projectionMatrix;
+        shadowMatrix = orthoProjectionMatrix * orthoViewMatrix;
+    } else {
+        projectionMatrix = orthoProjectionMatrix * orthoViewMatrix;
+        shadowMatrix = mat4(0.0);
+    }
+
+    modelViewMatrix = nmodelViewMatrix * transformMatrix;
     gl_Position = vec4(a_position, 1.0);
 }