Simplified rotation shader code.

2 files changed, 9 insertions, 13 deletions

diff --git a/shaders/bullet_fragment.glsl b/shaders/bullet_fragment.glsl
index 5e8becd..55e29ff 100644
--- a/shaders/bullet_fragment.glsl
+++ b/shaders/bullet_fragment.glsl
@@ -1,12 +1,9 @@
-varying mat4 v_tex_rot;
+varying mat3 v_tex_rot;
 uniform sampler2D tex;
 
 void main() {
 	vec2 l_uv = gl_TexCoord[0].xy;
-	const vec2 l_offset = vec2(0.5, 0.5);
-	l_uv -= l_offset;
-	l_uv = vec2(v_tex_rot * vec4(l_uv, 0.0, 1.0));
-	l_uv += l_offset;
+	l_uv = vec2(v_tex_rot * vec3(l_uv, 0.5));
 	gl_FragColor = texture2D(tex, l_uv);
 	float M = max(max(gl_FragColor.x, gl_FragColor.y), gl_FragColor.z);
 	float C = M - min(min(gl_FragColor.x, gl_FragColor.y), gl_FragColor.z);
diff --git a/shaders/bullet_vertex.glsl b/shaders/bullet_vertex.glsl
index 0843be2..0717b0a 100644
--- a/shaders/bullet_vertex.glsl
+++ b/shaders/bullet_vertex.glsl
@@ -1,14 +1,13 @@
-varying mat4 v_tex_rot;
+varying mat3 v_tex_rot;
 
 void main() {
 	vec4 l_position = gl_Vertex;
-	vec2 l_direction = normalize(vec2(l_position.z, l_position.w));
-	v_tex_rot = mat4(l_direction.x, l_direction.y, 0.0, 0.0,
-					-l_direction.y, l_direction.x, 0.0, 0.0,
-					0.0, 0.0, 1.0, 0.0,
-					0.0, 0.0, 0.0, 1.0);
-	l_position.z = 0.0;
-	l_position.w = 1.0;
+	vec2 l_direction = normalize(l_position.zw);
+	v_tex_rot = mat3(
+		l_direction.x, l_direction.y, 0.0,
+		-l_direction.y, l_direction.x, 0.0,
+		1.0 - l_direction.x + l_direction.y, 1.0 - l_direction.y - l_direction.x, 0.0);
+	l_position.zw = vec2(0.0, 1.0);
 	gl_FrontColor = gl_Color;
 	gl_Position = gl_ModelViewProjectionMatrix * l_position;
 }