mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-20 21:32:20 +02:00
128 lines
3.2 KiB
Go
128 lines
3.2 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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"fmt"
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"github.com/hajimehoshi/go-ebiten/graphics"
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"github.com/hajimehoshi/go-ebiten/graphics/matrix"
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"github.com/hajimehoshi/go-ebiten/graphics/opengl/shader"
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"math"
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)
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func glMatrix(matrix [4][4]float64) [16]float32 {
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result := [16]float32{}
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for j := 0; j < 4; j++ {
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for i := 0; i < 4; i++ {
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result[i+j*4] = float32(matrix[i][j])
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}
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}
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return result
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}
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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 newRTWithCurrentFramebuffer(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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return &RenderTarget{C.GLuint(framebuffer), width, height, true}
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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 (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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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) 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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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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func (r *RenderTarget) fill(red, green, blue uint8) {
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r.setAsViewport()
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const max = float64(math.MaxUint8)
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C.glClearColor(
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C.GLclampf(float64(red)/max),
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C.GLclampf(float64(green)/max),
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C.GLclampf(float64(blue)/max),
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1)
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C.glClear(C.GL_COLOR_BUFFER_BIT)
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}
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func (r *RenderTarget) drawTexture(
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texture *Texture,
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parts []graphics.TexturePart,
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geometryMatrix matrix.Geometry,
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colorMatrix matrix.Color) {
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r.setAsViewport()
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projectionMatrix := r.projectionMatrix()
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quads := graphics.TextureQuads(parts, texture.width, texture.height)
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shader.DrawTexture(
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shader.NativeTexture(texture.native),
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glMatrix(projectionMatrix),
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quads,
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geometryMatrix,
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colorMatrix)
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}
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