1 files changed, 69 insertions, 0 deletions
diff --git a/shaders/forest.geom b/shaders/forest.geom
new file mode 100644
index 0000000..0c0cafb
--- /dev/null
+++ b/shaders/forest.geom
@@ -0,0 +1,69 @@
+#version 150
+#extension GL_ARB_explicit_attrib_location : enable
+#extension GL_ARB_explicit_uniform_location : enable
+
+layout(points) in ;
+layout(triangle_strip, max_vertices=82) out;
+
+layout(location = 4) uniform mat4 pjMatrix ;
+layout(location = 5) uniform mat4 mvMatrix ;
+
+out vec2 texposition;
+out vec3 normal ;
+out vec4 frag_position ;
+
+void vertex( vec4 pos ) {
+    normal = - inverse(transpose(mat3(mvMatrix))) * vec3( pos.x, 0, pos.z ) ;
+    gl_Position = pjMatrix * (frag_position = gl_in[0].gl_Position + (mvMatrix * pos)) ;
+    EmitVertex() ;
+}
+
+void main() {
+    float r = 0.045 ;
+    float th = 0.00 ;
+    float h = 0.4 ;
+    for( ; th < 6.4 ; th += 1.0 ) {
+        float c = r * cos( th ) ;
+        float s = r * sin( th ) ;
+        float c2 = r * cos( th + 1.0 ) ;
+        float s2 = r * sin( th + 1.0 ) ;
+
+        float tex_x = th / 6.4 / 2.0;
+        float tex_x2 = (th+1.0) / 6.4 / 2.0 ;
+        texposition = vec2(tex_x, 0);
+        vertex( vec4(c, 0.0, s, 0) ) ;
+        texposition = vec2(tex_x, 1);
+        vertex( vec4(c, h, s, 0) ) ;
+        texposition = vec2(tex_x2, 0);
+        vertex( vec4(c2, h, s2, 0) ) ;
+
+        texposition = vec2(tex_x, 0);
+        vertex( vec4(c, 0.0, s, 0) ) ;
+        texposition = vec2(tex_x2, 0);
+        vertex( vec4(c2, 0, s2, 0) ) ;
+        texposition = vec2(tex_x2, 1);
+        vertex( vec4(c2, h, s2, 0) ) ;
+    }
+
+    for( th = 0; th < 6.4 ; th += 1.0 ) {
+        float c = (r*4) * cos( th ) ;
+        float s = (r*4) * sin( th ) ;
+        float tex_x = th / 6.4 / 2.0 + 0.5;
+        texposition = vec2(tex_x, 1);
+        vertex( vec4(0,h*2,0,0) ) ;
+        texposition = vec2(tex_x, 0);
+        vertex( vec4(s,h/2,c,0) ) ;
+    }
+
+    for( th = 0; th < 6.4 ; th += 1.0 ) {
+        float c = (r*6) * cos( th ) ;
+        float s = (r*6) * sin( th ) ;
+        float tex_x = th / 6.4 / 2.0 + 0.5;
+        texposition = vec2(tex_x, 1);
+        vertex( vec4(0,h,0,0) ) ;
+        texposition = vec2(tex_x, 0);
+        vertex( vec4(s,h/4,c,0) ) ;
+    }
+
+    EndPrimitive();
+}