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TextureRenderer.go
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TextureRenderer.go
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package render
import (
"unsafe"
"github.com/inkyblackness/hacked/ui/opengl"
)
// TextureRenderer is a renderer within which something can be rendered onto a texture.
// This texture can then be used to be displayed.
type TextureRenderer struct {
gl opengl.OpenGL
framebuffer uint32
texture uint32
width int32
height int32
}
// NewTextureRenderer returns a new instance.
func NewTextureRenderer(gl opengl.OpenGL) *TextureRenderer {
renderer := &TextureRenderer{
gl: gl,
framebuffer: gl.GenFramebuffers(1)[0],
texture: gl.GenTextures(1)[0],
width: 200,
height: 200,
}
gl.BindTexture(opengl.TEXTURE_2D, renderer.texture)
gl.TexParameteri(opengl.TEXTURE_2D, opengl.TEXTURE_MAG_FILTER, opengl.NEAREST)
gl.TexParameteri(opengl.TEXTURE_2D, opengl.TEXTURE_MIN_FILTER, opengl.NEAREST)
offset := unsafe.Pointer(uintptr(0)) // nolint: govet
gl.TexImage2D(opengl.TEXTURE_2D, 0, opengl.RGBA, renderer.width, renderer.height, 0, opengl.RGBA, opengl.UNSIGNED_BYTE, offset)
// gl.GenerateMipmap(opengl.TEXTURE_2D)
gl.BindTexture(opengl.TEXTURE_2D, 0)
renderer.onFramebuffer(func() {
gl.BindTexture(opengl.TEXTURE_2D, renderer.texture)
gl.FramebufferTexture(opengl.FRAMEBUFFER, opengl.COLOR_ATTACHMENT0, renderer.texture, 0)
gl.DrawBuffers([]uint32{opengl.COLOR_ATTACHMENT0})
gl.BindTexture(opengl.TEXTURE_2D, 0)
// result := gl.CheckFramebufferStatus(opengl.FRAMEBUFFER)
// fmt.Printf("status: 0x%04X\n", result)
// result == FRAMEBUFFER_COMPLETE == 0x8CD5
})
return renderer
}
// Dispose cleans up resources.
func (renderer *TextureRenderer) Dispose() {
gl := renderer.gl
gl.DeleteFramebuffers([]uint32{renderer.framebuffer})
gl.DeleteTextures([]uint32{renderer.texture})
}
// Handle returns the texture handle.
func (renderer *TextureRenderer) Handle() uint32 {
return renderer.texture
}
// Size returns the dimensions of the texture, in pixels.
func (renderer *TextureRenderer) Size() (width, height float32) {
return float32(renderer.width), float32(renderer.height)
}
// Render calls the nested function. All drawing commands within this function will end up in the texture.
func (renderer *TextureRenderer) Render(nested func()) {
gl := renderer.gl
renderer.onFramebuffer(func() {
gl.Viewport(0, 0, renderer.width, renderer.height)
gl.ClearColor(0.0, 0.0, 0.0, 0.0)
gl.Clear(opengl.COLOR_BUFFER_BIT | opengl.DEPTH_BUFFER_BIT)
nested()
})
}
func (renderer *TextureRenderer) onFramebuffer(nested func()) {
gl := renderer.gl
gl.BindFramebuffer(opengl.FRAMEBUFFER, renderer.framebuffer)
nested()
gl.BindFramebuffer(opengl.FRAMEBUFFER, 0)
}