mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
139 lines
3.4 KiB
Go
139 lines
3.4 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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"image"
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"image/draw"
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"unsafe"
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)
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func nextPowerOf2(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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type Texture struct {
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native 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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}
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type RenderTarget struct {
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texture *Texture
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framebuffer C.GLuint
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}
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func createNativeTexture(textureWidth, textureHeight int, pixels unsafe.Pointer) C.GLuint {
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nativeTexture := C.GLuint(0)
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C.glGenTextures(1, (*C.GLuint)(&nativeTexture))
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if nativeTexture < 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(nativeTexture))
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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, pixels)
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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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return nativeTexture
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}
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func createTexture(width, height int) *Texture {
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textureWidth := int(nextPowerOf2(uint64(width)))
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textureHeight := int(nextPowerOf2(uint64(height)))
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return &Texture{
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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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native: createNativeTexture(textureWidth, textureHeight, nil),
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}
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}
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func newRenderTarget(width, height int) (*RenderTarget, error) {
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texture := createTexture(width, height)
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framebuffer := createFramebuffer(texture.native)
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return &RenderTarget{
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texture: texture,
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framebuffer: framebuffer,
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}, nil
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}
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func newTextureFromImage(img image.Image) (*Texture, error) {
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size := img.Bounds().Size()
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width, height := size.X, size.Y
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textureWidth := int(nextPowerOf2(uint64(width)))
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textureHeight := int(nextPowerOf2(uint64(height)))
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adjustedImageBound := image.Rectangle{
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image.ZP,
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image.Point{textureWidth, textureHeight},
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}
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adjustedImage := image.NewNRGBA(adjustedImageBound)
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dstBound := image.Rectangle{
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image.ZP,
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img.Bounds().Size(),
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}
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draw.Draw(adjustedImage, dstBound, img, image.ZP, draw.Src)
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pixelsPtr := unsafe.Pointer(&adjustedImage.Pix[0])
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nativeTexture := createNativeTexture(textureWidth, textureHeight, pixelsPtr)
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return &Texture{
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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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native: nativeTexture,
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}, nil
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}
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func newRenderTargetWithFramebuffer(width, height int,
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framebuffer C.GLuint) *RenderTarget {
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texture := &Texture{
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width: width,
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height: height,
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textureWidth: int(nextPowerOf2(uint64(width))),
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textureHeight: int(nextPowerOf2(uint64(height))),
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}
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return &RenderTarget{
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texture: texture,
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framebuffer: framebuffer,
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}
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}
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func createFramebuffer(nativeTexture C.GLuint) C.GLuint {
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framebuffer := C.GLuint(0)
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C.glGenFramebuffers(1, &framebuffer)
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origFramebuffer := C.GLint(0)
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C.glGetIntegerv(C.GL_FRAMEBUFFER_BINDING, &origFramebuffer)
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C.glBindFramebuffer(C.GL_FRAMEBUFFER, framebuffer)
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C.glFramebufferTexture2D(C.GL_FRAMEBUFFER, C.GL_COLOR_ATTACHMENT0,
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C.GL_TEXTURE_2D, nativeTexture, 0)
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C.glBindFramebuffer(C.GL_FRAMEBUFFER, C.GLuint(origFramebuffer))
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if C.glCheckFramebufferStatus(C.GL_FRAMEBUFFER) !=
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C.GL_FRAMEBUFFER_COMPLETE {
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panic("creating framebuffer failed")
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}
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return framebuffer
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}
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