ebiten/internal/graphics/command.go

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2016-06-02 19:34:34 +02:00
// Copyright 2016 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package graphics
import (
"errors"
"fmt"
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"image/color"
"math"
"github.com/hajimehoshi/ebiten/internal/graphics/opengl"
)
type command interface {
Exec(context *opengl.Context) error
}
type commandQueue struct {
commands []command
indexOffsetInBytes int
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}
var theCommandQueue = &commandQueue{
commands: []command{},
}
func (q *commandQueue) Enqueue(command command) {
q.commands = append(q.commands, command)
}
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func (q *commandQueue) Flush(context *opengl.Context) error {
q.indexOffsetInBytes = 0
vertices := []int16{}
for _, c := range q.commands {
switch c := c.(type) {
case *drawImageCommand:
vertices = append(vertices, c.vertices...)
}
}
// TODO: Check if len(vertices) is too big
if 0 < len(vertices) {
context.BufferSubData(context.ArrayBuffer, vertices)
}
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for _, c := range q.commands {
if err := c.Exec(context); err != nil {
return err
}
}
q.commands = []command{}
return nil
}
type fillCommand struct {
dst *Framebuffer
color color.Color
}
func (c *fillCommand) Exec(context *opengl.Context) error {
if err := c.dst.setAsViewport(context); err != nil {
return err
}
cr, cg, cb, ca := c.color.RGBA()
const max = math.MaxUint16
r := float64(cr) / max
g := float64(cg) / max
b := float64(cb) / max
a := float64(ca) / max
return context.FillFramebuffer(r, g, b, a)
}
type drawImageCommand struct {
dst *Framebuffer
src *Texture
vertices []int16
geo Matrix
color Matrix
mode opengl.CompositeMode
}
func (c *drawImageCommand) Exec(context *opengl.Context) error {
if err := c.dst.setAsViewport(context); err != nil {
return err
}
context.BlendFunc(c.mode)
// NOTE: WebGL doesn't seem to have Check gl.MAX_ELEMENTS_VERTICES or gl.MAX_ELEMENTS_INDICES so far.
// Let's use them to compare to len(quads) in the future.
n := len(c.vertices) / 16
if n == 0 {
return nil
}
if MaxQuads < n/16 {
return errors.New(fmt.Sprintf("len(quads) must be equal to or less than %d", MaxQuads))
}
p := programContext{
state: &theOpenGLState,
program: theOpenGLState.programTexture,
context: context,
projectionMatrix: glMatrix(c.dst.projectionMatrix()),
texture: c.src.native,
geoM: c.geo,
colorM: c.color,
}
p.begin()
defer p.end()
// TODO: We should call glBindBuffer here?
// The buffer is already bound at begin() but it is counterintuitive.
context.DrawElements(context.Triangles, 6*n, theCommandQueue.indexOffsetInBytes)
theCommandQueue.indexOffsetInBytes += 6 * n * 2
return nil
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}
type replacePixelsCommand struct {
dst *Framebuffer
texture *Texture
pixels []uint8
}
func (c *replacePixelsCommand) Exec(context *opengl.Context) error {
// Filling with non black or white color is required here for glTexSubImage2D.
// Very mysterious but this actually works (Issue #186)
if err := c.dst.setAsViewport(context); err != nil {
return err
}
if err := context.FillFramebuffer(0, 0, 0.5, 1); err != nil {
return err
}
context.BindTexture(c.texture.native)
context.TexSubImage2D(c.pixels, c.texture.width, c.texture.height)
return nil
}