block shader: add "shine" effect

This wasn't difficult to implement, but I think doing a "real" lighting
calculation would give a better effect.

include/render.hpp

@@ -22,6 +22,7 @@ extern "C" {
                      uint uniform_normal_trans,
                      uint uniform_base_color,
                      uint uniform_light_pos,
+                     uint uniform_time,
                      struct game_state * state);
 
   void render_balls(struct mesh ball_mesh,

src/main.c

@@ -162,6 +162,7 @@ int main()
   uint block__uniform_normal_trans = glGetUniformLocation(block_program, "normal_trans");
   uint block__uniform_base_color = glGetUniformLocation(block_program, "base_color");
   uint block__uniform_light_pos = glGetUniformLocation(block_program, "light_pos");
+  uint block__uniform_time = glGetUniformLocation(block_program, "time");
 
   // font
 
@@ -332,6 +333,7 @@ int main()
                   block__uniform_normal_trans,
                   block__uniform_base_color,
                   block__uniform_light_pos,
+                  block__uniform_time,
                   &state);
 
     glDisable(GL_BLEND);

src/render.cpp

@@ -100,6 +100,7 @@ void render_blocks(mesh block_mesh,
                    uint uniform_normal_trans,
                    uint uniform_base_color,
                    uint uniform_light_pos,
+                   uint uniform_time,
                    struct game_state * state)
 {
   light_pos_theta += 0.01;
@@ -136,6 +137,8 @@ void render_blocks(mesh block_mesh,
   // render blocks
   //////////////////////////////////////////////////////////////////////
 
+  glUniform1f(uniform_time, state->time);
+
   mat4x4 a = aspect_mat();
   vec3 light_pos = _light_pos();
 

src/shader/block.fp.glsl

@@ -3,6 +3,8 @@
 uniform vec4 base_color;
 uniform vec3 light_pos;
 
+uniform float time;
+
 varying vec3 fp_position;
 varying vec2 fp_texture;
 varying vec3 fp_normal;
@@ -12,7 +14,23 @@ void main()
   vec3 light_dir = normalize(light_pos - fp_position);
   float diffuse = max(dot(fp_normal, light_dir), 0.0);
 
-  vec3 color = (diffuse + 0.5) * base_color.xyz;
+  float g = fp_position.x + fp_position.y;
+  float gt = g * 8.0 + time * 10;
+  float d = sin(gt) / 8.0;
+  d = abs(d);
+  d = 0.05 / d;
 
+  float sgt = sin(gt / 10);
+  if (sgt < 0.9)
+    d = 0;
+  else
+    d = (sgt - 0.9) * 10;
+
+  //d = d * sin(time);
+  d = pow(d, 32);
+
+  vec3 color = (diffuse + 0.5) * (base_color.xyz + max(d * 0.5, 0));
   gl_FragColor = vec4(color, base_color.w);
+
+  //gl_FragColor = vec4(d, 0, 0, base_color.w);
 }