mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 13:07:26 +01:00
139 lines
3.7 KiB
Go
139 lines
3.7 KiB
Go
// Copyright 2014 Hajime Hoshi
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package graphics
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import (
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"image/color"
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"math"
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"github.com/hajimehoshi/ebiten/internal/graphics/opengl"
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)
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func orthoProjectionMatrix(left, right, bottom, top int) *[4][4]float64 {
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e11 := float64(2) / float64(right-left)
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e22 := float64(2) / float64(top-bottom)
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e14 := -1 * float64(right+left) / float64(right-left)
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e24 := -1 * float64(top+bottom) / float64(top-bottom)
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return &[4][4]float64{
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{e11, 0, 0, e14},
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{0, e22, 0, e24},
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{0, 0, 1, 0},
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{0, 0, 0, 1},
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}
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}
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type Framebuffer struct {
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native opengl.Framebuffer
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width int
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height int
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flipY bool
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proMatrix *[4][4]float64
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}
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func NewZeroFramebuffer(c *opengl.Context, width, height int) (*Framebuffer, error) {
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r := &Framebuffer{
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width: width,
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height: height,
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flipY: true,
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}
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return r, nil
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}
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func NewFramebufferFromTexture(c *opengl.Context, texture *Texture) (*Framebuffer, error) {
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f, err := c.NewFramebuffer(opengl.Texture(texture.native))
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if err != nil {
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return nil, err
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}
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w, h := texture.Size()
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return &Framebuffer{
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native: f,
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width: w,
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height: h,
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}, nil
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}
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func (f *Framebuffer) Size() (width, height int) {
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return f.width, f.height
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}
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func (f *Framebuffer) Dispose(c *opengl.Context) error {
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// Don't delete the default framebuffer.
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if f.native == opengl.ZeroFramebuffer {
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return nil
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}
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c.DeleteFramebuffer(f.native)
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return nil
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}
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func (f *Framebuffer) setAsViewport(c *opengl.Context) error {
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width := int(NextPowerOf2Int32(int32(f.width)))
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height := int(NextPowerOf2Int32(int32(f.height)))
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return c.SetViewport(f.native, width, height)
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}
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func (f *Framebuffer) projectionMatrix() *[4][4]float64 {
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if f.proMatrix != nil {
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return f.proMatrix
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}
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width := int(NextPowerOf2Int32(int32(f.width)))
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height := int(NextPowerOf2Int32(int32(f.height)))
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m := orthoProjectionMatrix(0, width, 0, height)
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if f.flipY {
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m[1][1] *= -1
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m[1][3] += float64(f.height) / float64(NextPowerOf2Int32(int32(f.height))) * 2
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}
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f.proMatrix = m
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return f.proMatrix
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}
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func (f *Framebuffer) Fill(c *opengl.Context, clr color.Color) error {
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if err := f.setAsViewport(c); err != nil {
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return err
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}
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cr, cg, cb, ca := clr.RGBA()
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const max = math.MaxUint16
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r := float64(cr) / max
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g := float64(cg) / max
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b := float64(cb) / max
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a := float64(ca) / max
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return c.FillFramebuffer(r, g, b, a)
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}
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func (f *Framebuffer) DrawTexture(c *opengl.Context, t *Texture, vertices []int16, geo, clr Matrix, mode opengl.CompositeMode) error {
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if err := f.setAsViewport(c); err != nil {
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return err
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}
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p := f.projectionMatrix()
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return drawTexture(c, t.native, p, vertices, geo, clr, mode)
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}
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func (f *Framebuffer) Pixels(c *opengl.Context) ([]uint8, error) {
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w, h := f.Size()
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w, h = int(NextPowerOf2Int32(int32(w))), int(NextPowerOf2Int32(int32(h)))
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return c.FramebufferPixels(f.native, w, h)
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}
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func (f *Framebuffer) ReplacePixels(c *opengl.Context, t *Texture, p []uint8) error {
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// Filling with non black or white color is required here for glTexSubImage2D.
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// Very mysterious but this actually works (Issue #186)
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if err := f.Fill(c, color.RGBA{0, 0, 0x01, 0xff}); err != nil {
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return err
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}
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c.BindTexture(t.native)
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c.TexSubImage2D(p, t.width, t.height)
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return nil
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}
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