ebiten/graphics/opengl/shader/shader.go
2013-12-14 05:34:27 +09:00

119 lines
2.4 KiB
Go

package shader
// #cgo LDFLAGS: -framework OpenGL
//
// #include <OpenGL/gl.h>
// #include <stdlib.h>
import "C"
import (
"fmt"
"unsafe"
)
type shader struct {
native C.GLuint
shaderType C.GLenum
source string
}
type shaderId int
const (
shaderVertex shaderId = iota
shaderFragment
shaderColorMatrix
shaderSolidColor
)
var shaders = map[shaderId]*shader{
shaderVertex: &shader{
shaderType: C.GL_VERTEX_SHADER,
source: `
uniform mat4 projection_matrix;
uniform mat4 modelview_matrix;
attribute vec2 vertex;
attribute vec2 tex_coord;
varying vec2 vertex_out_tex_coord;
void main(void) {
vertex_out_tex_coord = tex_coord;
gl_Position = projection_matrix * modelview_matrix * vec4(vertex, 0, 1);
}
`,
},
shaderFragment: &shader{
shaderType: C.GL_FRAGMENT_SHADER,
source: `
uniform sampler2D texture;
varying vec2 vertex_out_tex_coord;
void main(void) {
gl_FragColor = texture2D(texture, vertex_out_tex_coord);
}
`,
},
shaderColorMatrix: &shader{
shaderType: C.GL_FRAGMENT_SHADER,
source: `
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);
gl_FragColor = (color_matrix * color) + color_matrix_translation;
}
`,
},
shaderSolidColor: &shader{
shaderType: C.GL_FRAGMENT_SHADER,
source: `
uniform vec4 color;
void main(void) {
gl_FragColor = color;
}
`,
},
}
func (s *shader) compile() {
s.native = C.glCreateShader(s.shaderType)
if s.native == 0 {
panic("glCreateShader failed")
}
csource := (*C.GLchar)(C.CString(s.source))
// TODO: defer?
// defer C.free(unsafe.Pointer(csource))
C.glShaderSource(s.native, 1, &csource, nil)
C.glCompileShader(s.native)
compiled := C.GLint(C.GL_FALSE)
C.glGetShaderiv(s.native, C.GL_COMPILE_STATUS, &compiled)
if compiled == C.GL_FALSE {
s.showShaderLog()
panic("shader compile failed")
}
}
func (s *shader) showShaderLog() {
logSize := C.GLint(0)
C.glGetShaderiv(s.native, C.GL_INFO_LOG_LENGTH, &logSize)
if logSize == 0 {
return
}
length := C.GLsizei(0)
buffer := make([]C.GLchar, logSize)
C.glGetShaderInfoLog(s.native, C.GLsizei(logSize), &length, &buffer[0])
message := string(C.GoBytes(unsafe.Pointer(&buffer[0]), C.int(length)))
fmt.Printf("shader error: %s\n", message)
}
func (s *shader) delete() {
C.glDeleteShader(s.native)
}