mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
75 lines
1.9 KiB
Go
75 lines
1.9 KiB
Go
// Copyright 2014 Hajime Hoshi
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package shader
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import (
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"github.com/hajimehoshi/ebiten/internal/opengl"
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"strings"
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)
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type shaderId int
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const (
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shaderVertex shaderId = iota
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shaderColorMatrix
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)
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func shader(c *opengl.Context, id shaderId) string {
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str := shaders[id]
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if !c.GlslHighpSupported() {
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str = strings.Replace(str, "highp ", "", -1)
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str = strings.Replace(str, "lowp ", "", -1)
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}
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return str
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}
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// TODO: Create version 100 for WebGL
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var shaders = map[shaderId]string{
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shaderVertex: `
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uniform highp mat4 projection_matrix;
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uniform highp mat4 modelview_matrix;
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attribute highp vec2 vertex;
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attribute highp vec2 tex_coord;
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varying highp vec2 vertex_out_tex_coord;
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void main(void) {
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vertex_out_tex_coord = tex_coord;
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gl_Position = projection_matrix * modelview_matrix * vec4(vertex, 0, 1);
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}
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`,
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shaderColorMatrix: `
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uniform lowp sampler2D texture;
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uniform lowp mat4 color_matrix;
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uniform lowp vec4 color_matrix_translation;
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varying highp vec2 vertex_out_tex_coord;
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void main(void) {
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lowp vec4 color = texture2D(texture, vertex_out_tex_coord);
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if (color_matrix != mat4(1.0) || color_matrix_translation != vec4(0.0)) {
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// Un-premultiply alpha
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color.rgb /= color.a;
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// Apply the color matrix
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color = (color_matrix * color) + color_matrix_translation;
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color = clamp(color, 0.0, 1.0);
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// Premultiply alpha
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color.rgb *= color.a;
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}
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gl_FragColor = color;
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}
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`,
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}
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