all: rename the gioui.org/ui module to gioui.org

The "ui" is redundant and stutters.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/internal/gpu/context.go

@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package gpu
+
+import (
+	"errors"
+	"strings"
+
+	"gioui.org/app/internal/gl"
+)
+
+type context struct {
+	caps caps
+	*gl.Functions
+}
+
+type caps struct {
+	EXT_disjoint_timer_query bool
+	// floatTriple holds the settings for floating point
+	// textures.
+	floatTriple textureTriple
+	// Single channel alpha textures.
+	alphaTriple textureTriple
+	srgbaTriple textureTriple
+}
+
+// textureTriple holds the type settings for
+// a TexImage2D call.
+type textureTriple struct {
+	internalFormat int
+	format         gl.Enum
+	typ            gl.Enum
+}
+
+func newContext(glctx gl.Context) (*context, error) {
+	ctx := &context{
+		Functions: glctx.Functions(),
+	}
+	exts := strings.Split(ctx.GetString(gl.EXTENSIONS), " ")
+	glVer := ctx.GetString(gl.VERSION)
+	ver, err := gl.ParseGLVersion(glVer)
+	if err != nil {
+		return nil, err
+	}
+	floatTriple, err := floatTripleFor(ctx, ver, exts)
+	if err != nil {
+		return nil, err
+	}
+	srgbaTriple, err := srgbaTripleFor(ver, exts)
+	if err != nil {
+		return nil, err
+	}
+	hasTimers := hasExtension(exts, "GL_EXT_disjoint_timer_query_webgl2") || hasExtension(exts, "GL_EXT_disjoint_timer_query")
+	ctx.caps = caps{
+		EXT_disjoint_timer_query: hasTimers,
+		floatTriple:              floatTriple,
+		alphaTriple:              alphaTripleFor(ver),
+		srgbaTriple:              srgbaTriple,
+	}
+	return ctx, nil
+}
+
+// floatTripleFor determines the best texture triple for floating point FBOs.
+func floatTripleFor(ctx *context, ver [2]int, exts []string) (textureTriple, error) {
+	var triples []textureTriple
+	if ver[0] >= 3 {
+		triples = append(triples, textureTriple{gl.R16F, gl.Enum(gl.RED), gl.Enum(gl.HALF_FLOAT)})
+	}
+	if hasExtension(exts, "GL_OES_texture_half_float") || hasExtension(exts, "EXT_color_buffer_half_float") {
+		triples = append(triples, textureTriple{gl.RGBA, gl.Enum(gl.RGBA), gl.Enum(gl.HALF_FLOAT_OES)})
+	}
+	if hasExtension(exts, "GL_OES_texture_float") || hasExtension(exts, "GL_EXT_color_buffer_float") {
+		triples = append(triples, textureTriple{gl.RGBA, gl.Enum(gl.RGBA), gl.Enum(gl.FLOAT)})
+	}
+	tex := ctx.CreateTexture()
+	defer ctx.DeleteTexture(tex)
+	ctx.BindTexture(gl.TEXTURE_2D, tex)
+	ctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
+	ctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
+	ctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+	ctx.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+	fbo := ctx.CreateFramebuffer()
+	defer ctx.DeleteFramebuffer(fbo)
+	defFBO := gl.Framebuffer(ctx.GetBinding(gl.FRAMEBUFFER_BINDING))
+	ctx.BindFramebuffer(gl.FRAMEBUFFER, fbo)
+	defer ctx.BindFramebuffer(gl.FRAMEBUFFER, defFBO)
+	for _, tt := range triples {
+		const size = 256
+		ctx.TexImage2D(gl.TEXTURE_2D, 0, tt.internalFormat, size, size, tt.format, tt.typ, nil)
+		ctx.FramebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0)
+		if st := ctx.CheckFramebufferStatus(gl.FRAMEBUFFER); st == gl.FRAMEBUFFER_COMPLETE {
+			return tt, nil
+		}
+	}
+	return textureTriple{}, errors.New("floating point fbos not supported")
+}
+
+func srgbaTripleFor(ver [2]int, exts []string) (textureTriple, error) {
+	switch {
+	case ver[0] >= 3:
+		return textureTriple{gl.SRGB8_ALPHA8, gl.Enum(gl.RGBA), gl.Enum(gl.UNSIGNED_BYTE)}, nil
+	case hasExtension(exts, "GL_EXT_sRGB"):
+		return textureTriple{gl.SRGB_ALPHA_EXT, gl.Enum(gl.SRGB_ALPHA_EXT), gl.Enum(gl.UNSIGNED_BYTE)}, nil
+	default:
+		return textureTriple{}, errors.New("no sRGB texture formats found")
+	}
+}
+
+func alphaTripleFor(ver [2]int) textureTriple {
+	intf, f := gl.R8, gl.Enum(gl.RED)
+	if ver[0] < 3 {
+		// R8, RED not supported on OpenGL ES 2.0.
+		intf, f = gl.LUMINANCE, gl.Enum(gl.LUMINANCE)
+	}
+	return textureTriple{intf, f, gl.UNSIGNED_BYTE}
+}
+
+func hasExtension(exts []string, ext string) bool {
+	for _, e := range exts {
+		if ext == e {
+			return true
+		}
+	}
+	return false
+}