mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
292 lines
7.8 KiB
Go
292 lines
7.8 KiB
Go
package opengl
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// #cgo LDFLAGS: -framework OpenGL
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//
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// #include <stdlib.h>
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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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"image/color"
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"unsafe"
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"github.com/hajimehoshi/go-ebiten/graphics"
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)
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type GraphicsContext struct {
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screenWidth int
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screenHeight int
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screenScale int
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mainFramebuffer C.GLuint
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projectionMatrix [16]float32
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currentShaderProgram C.GLuint
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framebuffers map[C.GLuint]C.GLuint
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}
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// This method should be called on the UI thread.
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func newGraphicsContext(screenWidth, screenHeight, screenScale int) *GraphicsContext {
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context := &GraphicsContext{
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screenWidth: screenWidth,
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screenHeight: screenHeight,
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screenScale: screenScale,
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mainFramebuffer: 0,
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framebuffers: map[C.GLuint]C.GLuint{},
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}
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// main framebuffer should be created sooner than any other framebuffers!
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mainFramebuffer := C.GLint(0)
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C.glGetIntegerv(C.GL_FRAMEBUFFER_BINDING, &mainFramebuffer)
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context.mainFramebuffer = C.GLuint(mainFramebuffer)
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initializeShaders()
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return context
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}
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var glTextureCache = map[*graphics.Texture]*Texture{}
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func glTexture(tex *graphics.Texture) *Texture {
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if glTex, ok := glTextureCache[tex]; ok {
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return glTex
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}
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var glTex *Texture = nil
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if tex.Image != nil {
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glTex = newTextureFromImage(tex.Image)
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} else {
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glTex = newTexture(tex.Width, tex.Height)
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}
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glTextureCache[tex] = glTex
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return glTex
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}
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func (context *GraphicsContext) Clear() {
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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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}
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func (context *GraphicsContext) Fill(clr color.Color) {
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r, g, b, a := clr.RGBA()
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max := 65535.0
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C.glClearColor(
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C.GLclampf(float64(r) / max),
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C.GLclampf(float64(g) / max),
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C.GLclampf(float64(b) / max),
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C.GLclampf(float64(a) / max))
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C.glClear(C.GL_COLOR_BUFFER_BIT)
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}
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func (context *GraphicsContext) DrawRect(x, y, width, height int, clr color.Color) {
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// TODO: implement!
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}
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func (context *GraphicsContext) DrawTexture(tex *graphics.Texture,
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srcX, srcY, srcWidth, srcHeight int,
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geometryMatrix *graphics.GeometryMatrix, colorMatrix *graphics.ColorMatrix) {
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geometryMatrix = geometryMatrix.Clone()
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colorMatrix = colorMatrix.Clone()
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texture := glTexture(tex)
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context.setShaderProgram(geometryMatrix, colorMatrix)
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C.glBindTexture(C.GL_TEXTURE_2D, texture.id)
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x1 := float32(0)
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x2 := float32(srcWidth)
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y1 := float32(0)
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y2 := float32(srcHeight)
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vertex := [...]float32{
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x1, y1,
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x2, y1,
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x1, y2,
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x2, y2,
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}
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tu1 := float32(srcX) / float32(texture.textureWidth)
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tu2 := float32(srcX + srcWidth) / float32(texture.textureWidth)
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tv1 := float32(srcY) / float32(texture.textureHeight)
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tv2 := float32(srcY + srcHeight) / float32(texture.textureHeight)
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texCoord := [...]float32{
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tu1, tv1,
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tu2, tv1,
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tu1, tv2,
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tu2, tv2,
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}
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vertexAttrLocation := getAttributeLocation(context.currentShaderProgram, "vertex")
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textureAttrLocation := getAttributeLocation(context.currentShaderProgram, "texture")
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C.glEnableClientState(C.GL_VERTEX_ARRAY)
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C.glEnableClientState(C.GL_TEXTURE_COORD_ARRAY)
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C.glEnableVertexAttribArray(C.GLuint(vertexAttrLocation))
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C.glEnableVertexAttribArray(C.GLuint(textureAttrLocation))
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C.glVertexAttribPointer(C.GLuint(vertexAttrLocation), 2, C.GL_FLOAT, C.GL_FALSE,
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0, unsafe.Pointer(&vertex[0]))
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C.glVertexAttribPointer(C.GLuint(textureAttrLocation), 2, C.GL_FLOAT, C.GL_FALSE,
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0, unsafe.Pointer(&texCoord[0]))
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C.glDrawArrays(C.GL_TRIANGLE_STRIP, 0, 4)
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C.glDisableVertexAttribArray(C.GLuint(textureAttrLocation))
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C.glDisableVertexAttribArray(C.GLuint(vertexAttrLocation))
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C.glDisableClientState(C.GL_TEXTURE_COORD_ARRAY)
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C.glDisableClientState(C.GL_VERTEX_ARRAY)
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}
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func abs(x int) int {
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if x < 0 {
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return -x
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}
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return x
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}
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func (context *GraphicsContext) SetOffscreen(tex *graphics.Texture) {
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C.glFlush()
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var texture *Texture = nil
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if tex != nil {
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texture = glTexture(tex)
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}
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framebuffer := C.GLuint(0)
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if texture != nil {
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framebuffer = context.getFramebuffer(texture)
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if framebuffer == context.mainFramebuffer {
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panic("invalid framebuffer")
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}
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} else {
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framebuffer = context.mainFramebuffer
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}
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C.glBindFramebuffer(C.GL_FRAMEBUFFER, framebuffer)
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if err := C.glCheckFramebufferStatus(C.GL_FRAMEBUFFER); 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.glEnable(C.GL_BLEND)
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C.glBlendFunc(C.GL_SRC_ALPHA, C.GL_ONE_MINUS_SRC_ALPHA)
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width, height, tx, ty := 0, 0, 0, 0
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if framebuffer != context.mainFramebuffer {
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width = texture.textureWidth
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height = texture.textureHeight
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tx = -1
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ty = -1
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} else {
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width = context.screenWidth * context.screenScale
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height = -1 * context.screenHeight * context.screenScale
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tx = -1
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ty = 1
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}
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C.glViewport(0, 0, C.GLsizei(abs(width)), C.GLsizei(abs(height)))
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e11 := float32(2.0) / float32(width)
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e22 := float32(2.0) / float32(height)
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e41 := float32(tx)
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e42 := float32(ty)
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context.projectionMatrix = [...]float32{
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e11, 0, 0, 0,
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0, e22, 0, 0,
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0, 0, 1, 0,
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e41, e42, 0, 1,
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}
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}
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func (context *GraphicsContext) resetOffscreen() {
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context.SetOffscreen(nil)
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}
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// This method should be called on the UI thread.
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func (context *GraphicsContext) flush() {
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C.glFlush()
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}
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// This method should be called on the UI thread.
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func (context *GraphicsContext) setShaderProgram(
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geometryMatrix *graphics.GeometryMatrix, colorMatrix *graphics.ColorMatrix) {
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program := C.GLuint(0)
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if colorMatrix.IsIdentity() {
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program = regularShaderProgram
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} else {
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program = colorMatrixShaderProgram
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}
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// TODO: cache and skip?
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C.glUseProgram(program)
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context.currentShaderProgram = program
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C.glUniformMatrix4fv(getUniformLocation(program, "projection_matrix"),
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1, C.GL_FALSE,
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(*C.GLfloat)(&context.projectionMatrix[0]))
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a := float32(geometryMatrix.A())
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b := float32(geometryMatrix.B())
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c := float32(geometryMatrix.C())
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d := float32(geometryMatrix.D())
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tx := float32(geometryMatrix.Tx())
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ty := float32(geometryMatrix.Ty())
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glModelviewMatrix := [...]float32{
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a, c, 0, 0,
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b, d, 0, 0,
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0, 0, 1, 0,
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tx, ty, 0, 1,
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}
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C.glUniformMatrix4fv(getUniformLocation(program, "modelview_matrix"),
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1, C.GL_FALSE,
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(*C.GLfloat)(&glModelviewMatrix[0]))
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C.glUniform1i(getUniformLocation(program, "texture"), 0)
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if program != colorMatrixShaderProgram {
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return
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}
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e := [4][5]float32{}
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for i := 0; i < 4; i++ {
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for j := 0; j < 5; j++ {
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e[i][j] = float32(colorMatrix.Element(i, j))
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}
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}
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glColorMatrix := [...]float32{
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e[0][0], e[0][1], e[0][2], e[0][3],
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e[1][0], e[1][1], e[1][2], e[1][3],
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e[2][0], e[2][1], e[2][2], e[2][3],
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e[3][0], e[3][1], e[3][2], e[3][3],
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}
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C.glUniformMatrix4fv(getUniformLocation(program, "color_matrix"),
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1, C.GL_FALSE, (*C.GLfloat)(&glColorMatrix[0]))
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glColorMatrixTranslation := [...]float32{
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e[0][4], e[1][4], e[2][4], e[3][4],
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}
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C.glUniform4fv(getUniformLocation(program, "color_matrix_translation"),
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1, (*C.GLfloat)(&glColorMatrixTranslation[0]))
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}
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// This method should be called on the UI thread.
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func (context *GraphicsContext) getFramebuffer(texture *Texture) C.GLuint{
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framebuffer, ok := context.framebuffers[texture.id]
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if ok {
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return framebuffer
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}
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newFramebuffer := C.GLuint(0)
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C.glGenFramebuffers(1, &newFramebuffer)
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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, newFramebuffer)
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C.glFramebufferTexture2D(C.GL_FRAMEBUFFER, C.GL_COLOR_ATTACHMENT0,
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C.GL_TEXTURE_2D, texture.id, 0)
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C.glBindFramebuffer(C.GL_FRAMEBUFFER, C.GLuint(origFramebuffer))
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if C.glCheckFramebufferStatus(C.GL_FRAMEBUFFER) != C.GL_FRAMEBUFFER_COMPLETE {
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panic("creating framebuffer failed")
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}
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context.framebuffers[texture.id] = newFramebuffer
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return newFramebuffer
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}
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// This method should be called on the UI thread.
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func (context *GraphicsContext) deleteFramebuffer(texture *Texture) {
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framebuffer, ok := context.framebuffers[texture.id]
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if !ok {
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// TODO: panic?
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return
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}
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C.glDeleteFramebuffers(1, &framebuffer)
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delete(context.framebuffers, texture.id)
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}
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