SuperTuxKart 1.5 upstream source (from official release tarball)

data/shaders/simple_particle.vert

@@ -0,0 +1,79 @@
+uniform int flips;
+uniform int sky;
+uniform vec3 view_position;
+uniform float billboard;
+
+#ifdef Explicit_Attrib_Location_Usable
+
+layout(location = 0) in vec3 Position;
+layout(location = 1) in vec4 color_lifetime;
+layout(location = 2) in vec2 size;
+
+layout(location = 3) in vec2 Texcoord;
+layout(location = 4) in vec2 quadcorner;
+
+layout(location = 6) in float anglespeed;
+#else
+
+in vec3 Position;
+in vec4 color_lifetime;
+in vec2 size;
+
+in vec2 Texcoord;
+in vec2 quadcorner;
+
+in float anglespeed;
+#endif
+
+out vec2 tc;
+out vec4 pc;
+
+vec4 getQuat(float half_sin, float half_cos)
+{
+    return normalize(vec4(vec3(0.0, 1.0, 0.0) * half_sin, half_cos));
+}
+
+void main(void)
+{
+    if (size.x == 0.0 && size.y == 0.0)
+    {
+        gl_Position = vec4(0.);
+        pc = vec4(0.0);
+        tc = vec2(0.0);
+        return;
+    }
+
+    float lifetime = size.y;
+    vec2 particle_size = mix(size.xx, size, billboard);
+    tc = Texcoord;
+    pc = color_lifetime.zyxw;
+
+    vec4 viewpos = vec4(0.);
+    if (flips == 1 || sky == 1)
+    {
+        vec4 quat = vec4(0.0);
+        if (flips == 1)
+        {
+            float angle = lifetime * anglespeed;
+            float sin_a = sin(mod(angle / 2.0, 6.283185307179586));
+            float cos_a = cos(mod(angle / 2.0, 6.283185307179586));
+            quat = getQuat(sin_a, cos_a);
+        }
+        else
+        {
+            vec3 diff = Position - view_position;
+            float angle = atan(diff.x, diff.z);
+            quat = getQuat(sin(angle / -2.0), cos(angle / -2.0));
+        }
+        vec3 newquadcorner = vec3(particle_size * quadcorner, 0.0);
+        newquadcorner = newquadcorner + 2.0 * cross(cross(newquadcorner,
+            quat.xyz) + quat.w * newquadcorner, quat.xyz);
+        viewpos = u_view_matrix * vec4(Position + newquadcorner, 1.0);
+    }
+    else
+    {
+        viewpos = u_view_matrix * vec4(Position, 1.0);
+        viewpos += vec4(particle_size * quadcorner, 0.0, 0.0);
+    }
+    gl_Position = u_projection_matrix * viewpos;
+}