Initial commit

2022-01-20 21:58:50 +08:00
commit b44d41ec66
86 changed files with 5415 additions and 0 deletions
--- a/internal/render/texture.go
+++ b/internal/render/texture.go
@@ -0,0 +1,143 @@
+package render
+
+import (
+	"image"
+
+	"github.com/go-gl/gl/all-core/gl"
+)
+
+func curTextureBinding() uint32 {
+	var id int32
+	gl.GetIntegerv(gl.TEXTURE_BINDING_2D, &id)
+	return uint32(id)
+}
+
+// Texture holds handle to OpenGL Texture on the graphics card memory.
+type Texture struct {
+	tex uint32
+
+	hasMipmap bool
+}
+
+// NewTexture creates a new, empty Texture.
+func NewTexture() *Texture {
+	// Restore current texture binding
+	defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
+
+	var tex uint32
+
+	gl.GenTextures(1, &tex)
+	gl.BindTexture(gl.TEXTURE_2D, tex)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
+
+	return &Texture{tex: tex}
+}
+
+// NewTextureRGBA creates a new Texture with image.
+func NewTextureRGBA(image *image.RGBA) *Texture {
+	// Restore current texture binding
+	defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
+
+	var tex uint32
+
+	gl.GenTextures(1, &tex)
+	gl.BindTexture(gl.TEXTURE_2D, tex)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
+
+	gl.TexImage2D(
+		gl.TEXTURE_2D,
+		0,
+		gl.RGBA,
+		int32(image.Rect.Size().X),
+		int32(image.Rect.Size().Y),
+		0,
+		gl.RGBA,
+		gl.UNSIGNED_BYTE,
+		gl.Ptr(image.Pix),
+	)
+
+	return &Texture{tex: tex}
+}
+
+// SetSmooth sets the min/mag filters to LINEAR(smooth) or NEAREST(not smooth)
+// TODO: Not working
+func (t *Texture) SetSmooth(smooth bool) {
+	defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
+	gl.BindTexture(gl.TEXTURE_2D, t.tex)
+	if smooth {
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+	} else {
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+	}
+}
+
+// UpdateRGBA updates the content of the texture with image.
+// It deletes existing mipmap, you need to generate it again.
+func (t *Texture) UpdateRGBA(image *image.RGBA) {
+
+	// Restore current texture binding
+	defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
+
+	gl.BindTexture(gl.TEXTURE_2D, t.tex)
+	gl.TexImage2D(
+		gl.TEXTURE_2D,
+		0,
+		gl.RGBA,
+		int32(image.Rect.Size().X),
+		int32(image.Rect.Size().Y),
+		0,
+		gl.RGBA,
+		gl.UNSIGNED_BYTE,
+		gl.Ptr(image.Pix),
+	)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+
+	t.hasMipmap = false
+
+}
+
+// GenerateMipMap generates mipmap for the texture.
+func (t *Texture) GenerateMipMap() {
+
+	// Restore current texture binding
+	defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
+
+	gl.BindTexture(gl.TEXTURE_2D, t.tex)
+	gl.GenerateMipmap(gl.TEXTURE_2D)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST_MIPMAP_LINEAR)
+
+	t.hasMipmap = true
+
+}
+
+// InvalidateMipMap invalidates mipmap for the texture.
+func (t *Texture) InvalidateMipMap() {
+
+	// Restore current texture binding
+	defer gl.BindTexture(gl.TEXTURE_2D, curTextureBinding())
+
+	gl.BindTexture(gl.TEXTURE_2D, t.tex)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+
+	t.hasMipmap = false
+}
+
+// Handle returns the OpenGL handle of the texture.
+func (t *Texture) Handle() uint32 {
+	return t.tex
+}
+
+// Free deletes the texture.
+func (t *Texture) Free() {
+	if t.tex != 0 {
+		gl.DeleteTextures(1, &t.tex)
+	}
+}