ebiten/graphics/opengl/texture.go
2013-10-27 02:25:41 +09:00

82 lines
2.4 KiB
Go

package opengl
// #cgo LDFLAGS: -framework OpenGL
//
// #include <OpenGL/gl.h>
import "C"
import (
"github.com/hajimehoshi/go-ebiten/graphics/rendertarget"
"github.com/hajimehoshi/go-ebiten/graphics/texture"
"image"
"unsafe"
)
func createNativeTexture(textureWidth, textureHeight int, pixels []uint8) C.GLuint {
nativeTexture := C.GLuint(0)
C.glGenTextures(1, (*C.GLuint)(&nativeTexture))
if nativeTexture < 0 {
panic("glGenTexture failed")
}
C.glPixelStorei(C.GL_UNPACK_ALIGNMENT, 4)
C.glBindTexture(C.GL_TEXTURE_2D, C.GLuint(nativeTexture))
defer C.glBindTexture(C.GL_TEXTURE_2D, 0)
C.glTexParameteri(C.GL_TEXTURE_2D, C.GL_TEXTURE_MAG_FILTER, C.GL_LINEAR)
C.glTexParameteri(C.GL_TEXTURE_2D, C.GL_TEXTURE_MIN_FILTER, C.GL_LINEAR)
ptr := unsafe.Pointer(nil)
if pixels != nil {
ptr = unsafe.Pointer(&pixels[0])
}
C.glTexImage2D(C.GL_TEXTURE_2D, 0, C.GL_RGBA,
C.GLsizei(textureWidth), C.GLsizei(textureHeight),
0, C.GL_RGBA, C.GL_UNSIGNED_BYTE, ptr)
return nativeTexture
}
func create(textureWidth, textureHeight int) (interface{}, error) {
return createNativeTexture(textureWidth, textureHeight, nil), nil
}
func createFromImage(img *image.NRGBA) (interface{}, error) {
size := img.Bounds().Size()
return createNativeTexture(size.X, size.Y, img.Pix), nil
}
func newRenderTarget(width, height int) (*rendertarget.RenderTarget, error) {
texture, err := texture.New(width, height, create)
if err != nil {
return nil, err
}
framebuffer := createFramebuffer(texture.Native().(C.GLuint))
return rendertarget.NewWithFramebuffer(texture, framebuffer), nil
}
func newRenderTargetWithFramebuffer(width, height int, framebuffer C.GLuint) (*rendertarget.RenderTarget, error) {
texture, err := texture.New(width, height, create)
if err != nil {
return nil, err
}
return rendertarget.NewWithFramebuffer(texture, framebuffer), nil
}
func createFramebuffer(nativeTexture C.GLuint) C.GLuint {
framebuffer := C.GLuint(0)
C.glGenFramebuffers(1, &framebuffer)
origFramebuffer := C.GLint(0)
C.glGetIntegerv(C.GL_FRAMEBUFFER_BINDING, &origFramebuffer)
C.glBindFramebuffer(C.GL_FRAMEBUFFER, framebuffer)
C.glFramebufferTexture2D(C.GL_FRAMEBUFFER, C.GL_COLOR_ATTACHMENT0,
C.GL_TEXTURE_2D, nativeTexture, 0)
C.glBindFramebuffer(C.GL_FRAMEBUFFER, C.GLuint(origFramebuffer))
if C.glCheckFramebufferStatus(C.GL_FRAMEBUFFER) !=
C.GL_FRAMEBUFFER_COMPLETE {
panic("creating framebuffer failed")
}
return framebuffer
}