mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
135 lines
2.9 KiB
Go
135 lines
2.9 KiB
Go
package opengl
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// #cgo LDFLAGS: -framework OpenGL
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//
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// #include <OpenGL/gl.h>
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import "C"
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import (
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"github.com/hajimehoshi/go-ebiten/graphics"
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"image"
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"unsafe"
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)
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func clp2(x uint64) uint64 {
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x -= 1
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x |= (x >> 1)
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x |= (x >> 2)
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x |= (x >> 4)
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x |= (x >> 8)
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x |= (x >> 16)
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x |= (x >> 32)
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return x + 1
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}
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func adjustPixels(width, height int, pixels []uint8) []uint8 {
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textureWidth := int(clp2(uint64(width)))
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textureHeight := int(clp2(uint64(height)))
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if width == textureWidth && height == textureHeight {
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return pixels
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}
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newPixels := make([]uint8, textureWidth*textureHeight*4)
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for j := 0; j < height; j++ {
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copy(newPixels[textureWidth*4*j:],
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pixels[width*4*j:width*4*j+width*4])
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}
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return newPixels
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}
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type Texture struct {
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id C.GLuint
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width int
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height int
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textureWidth int
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textureHeight int
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framebuffer C.GLuint
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}
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func (texture *Texture) ID() graphics.TextureID {
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return graphics.TextureID(texture.id)
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}
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func (texture *Texture) Width() int {
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return texture.width
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}
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func (texture *Texture) Height() int {
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return texture.height
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}
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func createTexture(width, height int, pixels []uint8) *Texture {
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if pixels != nil {
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pixels = adjustPixels(width, height, pixels)
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}
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textureWidth := int(clp2(uint64(width)))
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textureHeight := int(clp2(uint64(height)))
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texture := &Texture{
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id: 0,
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width: width,
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height: height,
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textureWidth: textureWidth,
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textureHeight: textureHeight,
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}
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textureID := C.GLuint(0)
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C.glGenTextures(1, (*C.GLuint)(&textureID))
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if textureID < 0 {
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panic("glGenTexture failed")
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}
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C.glPixelStorei(C.GL_UNPACK_ALIGNMENT, 4)
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C.glBindTexture(C.GL_TEXTURE_2D, C.GLuint(textureID))
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ptr := unsafe.Pointer(nil)
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if pixels != nil {
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ptr = unsafe.Pointer(&pixels[0])
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}
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C.glTexImage2D(C.GL_TEXTURE_2D, 0, C.GL_RGBA,
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C.GLsizei(textureWidth), C.GLsizei(textureHeight),
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0, C.GL_RGBA, C.GL_UNSIGNED_BYTE, ptr)
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C.glTexParameteri(C.GL_TEXTURE_2D, C.GL_TEXTURE_MAG_FILTER, C.GL_LINEAR)
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C.glTexParameteri(C.GL_TEXTURE_2D, C.GL_TEXTURE_MIN_FILTER, C.GL_LINEAR)
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C.glBindTexture(C.GL_TEXTURE_2D, 0)
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texture.id = textureID
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return texture
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}
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type textureError string
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func (err textureError) Error() string {
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return "Texture Error: " + string(err)
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}
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func newRenderTarget(width, height int) *Texture {
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return createTexture(width, height, nil)
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}
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func newTextureFromImage(img image.Image) (*Texture, error) {
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var pix []uint8
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switch img.(type) {
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case *image.RGBA:
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pix = img.(*image.RGBA).Pix
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case *image.NRGBA:
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pix = img.(*image.NRGBA).Pix
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default:
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return nil, textureError("image format must be RGBA or NRGBA")
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}
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size := img.Bounds().Size()
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return createTexture(size.X, size.Y, pix), nil
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}
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func newRenderTargetWithFramebuffer(width, height int,
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framebuffer C.GLuint) *Texture {
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return &Texture{
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id: 0,
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width: width,
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height: height,
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textureWidth: int(clp2(uint64(width))),
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textureHeight: int(clp2(uint64(height))),
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framebuffer: framebuffer,
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}
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}
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