ebiten/internal/opengl/framebuffer.go

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// Copyright 2014 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.
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package opengl
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// framebuffer is a wrapper of OpenGL's framebuffer.
type framebuffer struct {
native framebufferNative
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proMatrix []float32
width int
height int
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}
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// newFramebufferFromTexture creates a framebuffer from the given texture.
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func newFramebufferFromTexture(texture textureNative, width, height int) (*framebuffer, error) {
native, err := theContext.newFramebuffer(texture)
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if err != nil {
return nil, err
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}
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return &framebuffer{
native: native,
width: width,
height: height,
}, nil
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}
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// newScreenFramebuffer creates a framebuffer for the screen.
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func newScreenFramebuffer(width, height int) *framebuffer {
return &framebuffer{
native: theContext.getScreenFramebuffer(),
width: width,
height: height,
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}
}
// projectionMatrix returns a projection matrix of the framebuffer.
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//
// A projection matrix converts the coodinates on the framebuffer
// (0, 0) - (viewport width, viewport height)
// to the normalized device coodinates (-1, -1) - (1, 1) with adjustment.
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func (f *framebuffer) projectionMatrix() []float32 {
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if f.proMatrix != nil {
return f.proMatrix
}
f.proMatrix = orthoProjectionMatrix(0, f.width, 0, f.height)
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return f.proMatrix
}
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func (f *framebuffer) delete() {
if f.native != theContext.getScreenFramebuffer() {
theContext.deleteFramebuffer(f.native)
}
}