ebiten/graphics/opengl/context.go
2014-05-04 03:29:45 +09:00

123 lines
2.5 KiB
Go

package opengl
// #cgo LDFLAGS: -framework OpenGL
//
// #include <stdlib.h>
// #include <OpenGL/gl.h>
import "C"
import (
"github.com/hajimehoshi/go-ebiten/graphics"
"github.com/hajimehoshi/go-ebiten/graphics/matrix"
)
func enableAlphaBlending() {
C.glEnable(C.GL_TEXTURE_2D)
C.glEnable(C.GL_BLEND)
}
func flush() {
C.glFlush()
}
type Context struct {
screenId graphics.RenderTargetId
defaultId graphics.RenderTargetId
currentId graphics.RenderTargetId
ids *ids
screenWidth int
screenHeight int
screenScale int
}
func newContext(ids *ids, screenWidth, screenHeight, screenScale int) *Context {
context := &Context{
ids: ids,
screenWidth: screenWidth,
screenHeight: screenHeight,
screenScale: screenScale,
}
defaultRenderTarget := &RenderTarget{
framebuffer: C.GLuint(0),
width: screenWidth * screenScale,
height: screenHeight * screenScale,
flipY: true,
}
context.defaultId = context.ids.addRenderTarget(defaultRenderTarget)
var err error
context.screenId, err = ids.createRenderTarget(
screenWidth, screenHeight, graphics.FilterNearest)
if err != nil {
panic("initializing the offscreen failed: " + err.Error())
}
context.ResetOffscreen()
context.Clear()
enableAlphaBlending()
return context
}
func (c *Context) Dispose() {
// TODO: remove the default framebuffer?
c.ids.deleteRenderTarget(c.screenId)
}
func (c *Context) Update(draw func(graphics.Context)) {
c.ResetOffscreen()
c.Clear()
draw(c)
c.SetOffscreen(c.defaultId)
c.Clear()
scale := float64(c.screenScale)
geo := matrix.IdentityGeometry()
geo.Scale(scale, scale)
graphics.DrawWhole(
c.RenderTarget(c.screenId),
c.screenWidth,
c.screenHeight,
geo,
matrix.IdentityColor())
flush()
}
func (c *Context) Clear() {
c.Fill(0, 0, 0)
}
func (c *Context) Fill(r, g, b uint8) {
c.ids.fillRenderTarget(c.currentId, r, g, b)
}
func (c *Context) Texture(id graphics.TextureId) graphics.Drawer {
return &textureWithContext{id, c}
}
func (c *Context) RenderTarget(id graphics.RenderTargetId) graphics.Drawer {
return &textureWithContext{c.ids.toTexture(id), c}
}
func (c *Context) ResetOffscreen() {
c.currentId = c.screenId
}
func (c *Context) SetOffscreen(renderTargetId graphics.RenderTargetId) {
c.currentId = renderTargetId
}
type textureWithContext struct {
id graphics.TextureId
context *Context
}
func (t *textureWithContext) Draw(
parts []graphics.TexturePart,
geo matrix.Geometry,
color matrix.Color) {
t.context.ids.drawTexture(t.context.currentId, t.id, parts, geo, color)
}