ebiten/graphics/opengl/texture.go
2013-07-13 02:23:09 +09:00

156 lines
4.0 KiB
Go

// Copyright 2013 Hajime Hoshi
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
package opengl
// #cgo LDFLAGS: -framework OpenGL
//
// #include <OpenGL/gl.h>
import "C"
import (
"github.com/hajimehoshi/go.ebiten/graphics"
"image"
"unsafe"
)
func clp2(x uint64) uint64 {
x -= 1
x |= (x >> 1)
x |= (x >> 2)
x |= (x >> 4)
x |= (x >> 8)
x |= (x >> 16)
x |= (x >> 32)
return x + 1
}
func adjustPixels(width, height int, pixels []uint8) []uint8 {
textureWidth := int(clp2(uint64(width)))
textureHeight := int(clp2(uint64(height)))
if width == textureWidth && height == textureHeight {
return pixels
}
newPixels := make([]uint8, textureWidth*textureHeight*4)
for j := 0; j < height; j++ {
copy(newPixels[textureWidth*4*j:],
pixels[width*4*j:width*4*j+width*4])
}
return newPixels
}
type Texture struct {
id C.GLuint
width int
height int
textureWidth int
textureHeight int
framebuffer C.GLuint
isVirtual bool
}
func (texture *Texture) ID() graphics.TextureID {
return graphics.TextureID(texture.id)
}
func (texture *Texture) Width() int {
return texture.width
}
func (texture *Texture) Height() int {
return texture.height
}
func createTexture(width, height int, pixels []uint8) *Texture {
if pixels != nil {
pixels = adjustPixels(width, height, pixels)
}
textureWidth := int(clp2(uint64(width)))
textureHeight := int(clp2(uint64(height)))
texture := &Texture{
id: 0,
width: width,
height: height,
textureWidth: textureWidth,
textureHeight: textureHeight,
isVirtual: false,
}
textureID := C.GLuint(0)
C.glGenTextures(1, (*C.GLuint)(&textureID))
if textureID < 0 {
panic("glGenTexture failed")
}
C.glPixelStorei(C.GL_UNPACK_ALIGNMENT, 4)
C.glBindTexture(C.GL_TEXTURE_2D, C.GLuint(textureID))
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)
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)
C.glBindTexture(C.GL_TEXTURE_2D, 0)
texture.id = textureID
return texture
}
type textureError string
func (err textureError) Error() string {
return "Texture Error: " + string(err)
}
func newTexture(width, height int) *Texture {
return createTexture(width, height, nil)
}
func newTextureFromImage(img image.Image) (*Texture, error) {
var pix []uint8
switch img.(type) {
case *image.RGBA:
pix = img.(*image.RGBA).Pix
case *image.NRGBA:
pix = img.(*image.NRGBA).Pix
default:
return nil, textureError("image format must be RGBA or NRGBA")
}
size := img.Bounds().Size()
return createTexture(size.X, size.Y, pix), nil
}
func newVirtualTexture(width, height int) *Texture {
return &Texture{
id: 0,
width: width,
height: height,
textureWidth: int(clp2(uint64(width))),
textureHeight: int(clp2(uint64(height))),
isVirtual: true,
}
}