ebiten/internal/graphics/shader.go

79 lines
1.9 KiB
Go

// Copyright 2014 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package graphics
type shaderId int
const (
shaderVertexModelview shaderId = iota
shaderFragmentTexture
)
func shader(id shaderId) string {
return shaders[id]
}
var shaders = map[shaderId]string{
shaderVertexModelview: `
uniform mat4 projection_matrix;
attribute vec2 vertex;
attribute vec2 tex_coord;
attribute vec4 geo_matrix_body;
attribute vec2 geo_matrix_translation;
varying vec2 vertex_out_tex_coord;
void main(void) {
vertex_out_tex_coord = tex_coord;
mat4 geo_matrix = mat4(
vec4(geo_matrix_body[0], geo_matrix_body[2], 0, 0),
vec4(geo_matrix_body[1], geo_matrix_body[3], 0, 0),
vec4(0, 0, 1, 0),
vec4(geo_matrix_translation, 0, 1)
);
gl_Position = projection_matrix * geo_matrix * vec4(vertex, 0, 1);
}
`,
shaderFragmentTexture: `
#if defined(GL_ES)
precision mediump float;
#else
#define lowp
#define mediump
#define highp
#endif
uniform sampler2D texture;
uniform mat4 color_matrix;
uniform vec4 color_matrix_translation;
varying vec2 vertex_out_tex_coord;
void main(void) {
vec4 color = texture2D(texture, vertex_out_tex_coord);
// Un-premultiply alpha
if (0.0 < color.a) {
color.rgb /= color.a;
}
// Apply the color matrix
color = (color_matrix * color) + color_matrix_translation;
color = clamp(color, 0.0, 1.0);
// Premultiply alpha
color.rgb *= color.a;
gl_FragColor = color;
}
`,
}