mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
101 lines
2.6 KiB
Go
101 lines
2.6 KiB
Go
package rendertarget
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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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"fmt"
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"github.com/hajimehoshi/go-ebiten/graphics"
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)
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type NativeTexture C.GLuint
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type RenderTarget struct {
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framebuffer C.GLuint
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width int
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height int
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flipY bool
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}
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func NewWithCurrentFramebuffer(width, height int) *RenderTarget {
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framebuffer := C.GLint(0)
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C.glGetIntegerv(C.GL_FRAMEBUFFER_BINDING, &framebuffer)
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rt := &RenderTarget{C.GLuint(framebuffer), width, height, true}
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rt.setAsViewport()
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return rt
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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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defer C.glBindFramebuffer(C.GL_FRAMEBUFFER, C.GLuint(origFramebuffer))
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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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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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// Set this framebuffer opaque because alpha values on a target might be
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// confusing.
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C.glClearColor(0, 0, 0, 1)
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C.glClear(C.GL_COLOR_BUFFER_BIT)
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return framebuffer
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}
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func CreateFromTexture(native NativeTexture, width, height int) *RenderTarget {
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framebuffer := createFramebuffer(C.GLuint(native))
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return &RenderTarget{framebuffer, width, height, false}
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}
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func (r *RenderTarget) setAsViewport() {
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C.glFlush()
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C.glBindFramebuffer(C.GL_FRAMEBUFFER, C.GLuint(r.framebuffer))
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err := C.glCheckFramebufferStatus(C.GL_FRAMEBUFFER)
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if err != C.GL_FRAMEBUFFER_COMPLETE {
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panic(fmt.Sprintf("glBindFramebuffer failed: %d", err))
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}
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C.glBlendFuncSeparate(C.GL_SRC_ALPHA, C.GL_ONE_MINUS_SRC_ALPHA,
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C.GL_ZERO, C.GL_ONE)
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width := graphics.AdjustSizeForTexture(r.width)
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height := graphics.AdjustSizeForTexture(r.height)
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C.glViewport(0, 0, C.GLsizei(width), C.GLsizei(height))
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}
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func (r *RenderTarget) SetAsViewport() {
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current := C.GLint(0)
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C.glGetIntegerv(C.GL_FRAMEBUFFER_BINDING, ¤t)
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if C.GLuint(current) == r.framebuffer {
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return
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}
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r.setAsViewport()
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}
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func (r *RenderTarget) ProjectionMatrix() [4][4]float64 {
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width := graphics.AdjustSizeForTexture(r.width)
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height := graphics.AdjustSizeForTexture(r.height)
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matrix := graphics.OrthoProjectionMatrix(0, width, 0, height)
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if r.flipY {
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// Flip Y and move to fit with the top of the window.
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matrix[1][1] *= -1
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matrix[1][3] += float64(r.height) /
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float64(graphics.AdjustSizeForTexture(r.height)) * 2
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}
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return matrix
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}
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func (r *RenderTarget) Dispose() {
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C.glDeleteFramebuffers(1, &r.framebuffer)
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}
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