144 lines
3.5 KiB
Go
144 lines
3.5 KiB
Go
package render
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import (
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"image"
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"github.com/go-gl/gl/all-core/gl"
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)
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func curTextureBinding() uint32 {
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var id int32
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gl.GetIntegerv(gl.TEXTURE_BINDING_2D, &id)
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return uint32(id)
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}
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// Texture holds handle to OpenGL Texture on the graphics card memory.
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type Texture struct {
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tex uint32
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hasMipmap bool
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}
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// NewTexture creates a new, empty Texture.
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func NewTexture() *Texture {
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// Restore current texture binding
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defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
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var tex uint32
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gl.GenTextures(1, &tex)
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gl.BindTexture(gl.TEXTURE_2D, tex)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
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return &Texture{tex: tex}
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}
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// NewTextureRGBA creates a new Texture with image.
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func NewTextureRGBA(image *image.RGBA) *Texture {
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// Restore current texture binding
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defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
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var tex uint32
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gl.GenTextures(1, &tex)
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gl.BindTexture(gl.TEXTURE_2D, tex)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
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gl.TexImage2D(
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gl.TEXTURE_2D,
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0,
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gl.RGBA,
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int32(image.Rect.Size().X),
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int32(image.Rect.Size().Y),
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0,
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gl.RGBA,
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gl.UNSIGNED_BYTE,
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gl.Ptr(image.Pix),
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)
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return &Texture{tex: tex}
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}
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// SetSmooth sets the min/mag filters to LINEAR(smooth) or NEAREST(not smooth)
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// TODO: Not working
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func (t *Texture) SetSmooth(smooth bool) {
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defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
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gl.BindTexture(gl.TEXTURE_2D, t.tex)
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if smooth {
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
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} else {
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
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}
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}
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// UpdateRGBA updates the content of the texture with image.
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// It deletes existing mipmap, you need to generate it again.
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func (t *Texture) UpdateRGBA(image *image.RGBA) {
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// Restore current texture binding
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defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
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gl.BindTexture(gl.TEXTURE_2D, t.tex)
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gl.TexImage2D(
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gl.TEXTURE_2D,
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0,
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gl.RGBA,
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int32(image.Rect.Size().X),
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int32(image.Rect.Size().Y),
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0,
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gl.RGBA,
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gl.UNSIGNED_BYTE,
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gl.Ptr(image.Pix),
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)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
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t.hasMipmap = false
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}
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// GenerateMipMap generates mipmap for the texture.
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func (t *Texture) GenerateMipMap() {
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// Restore current texture binding
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defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
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gl.BindTexture(gl.TEXTURE_2D, t.tex)
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gl.GenerateMipmap(gl.TEXTURE_2D)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST_MIPMAP_LINEAR)
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t.hasMipmap = true
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}
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// InvalidateMipMap invalidates mipmap for the texture.
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func (t *Texture) InvalidateMipMap() {
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// Restore current texture binding
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defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
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gl.BindTexture(gl.TEXTURE_2D, t.tex)
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gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
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t.hasMipmap = false
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}
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// Handle returns the OpenGL handle of the texture.
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func (t *Texture) Handle() uint32 {
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return t.tex
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}
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// Free deletes the texture.
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func (t *Texture) Free() {
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if t.tex != 0 {
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gl.DeleteTextures(1, &t.tex)
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}
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}
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