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Refresh this package to the new API of the github.com/go-gl/gl package. It looses dependency on the github/go-gl/glh package.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,20 @@ | ||
| // Copyright 2012 The go-gl Authors. All rights reserved. | ||
| // Use of this source code is governed by a BSD-style | ||
| // license that can be found in the LICENSE file. | ||
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| package gltext | ||
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| import ( | ||
| "fmt" | ||
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| "github.com/go-gl/gl/v2.1/gl" | ||
| ) | ||
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| // checkGLError returns an opengl error if one exists. | ||
| func checkGLError() error { | ||
| errno := gl.GetError() | ||
| if errno == gl.NO_ERROR { | ||
| return nil | ||
| } | ||
| return fmt.Errorf("GL error: %d", errno) | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,94 @@ | ||
| // Copyright 2012 The go-gl Authors. All rights reserved. | ||
| // Use of this source code is governed by a BSD-style | ||
| // license that can be found in the LICENSE file. | ||
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| package gltext | ||
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| import ( | ||
| "fmt" | ||
| "image" | ||
| "image/color" | ||
| ) | ||
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| // Pow2 returns the first power-of-two value >= to n. | ||
| // This can be used to create suitable texture dimensions. | ||
| func Pow2(x uint32) uint32 { | ||
| x-- | ||
| x |= x >> 1 | ||
| x |= x >> 2 | ||
| x |= x >> 4 | ||
| x |= x >> 8 | ||
| x |= x >> 16 | ||
| return x + 1 | ||
| } | ||
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| // IsPow2 returns true if the given value is a power-of-two. | ||
| func IsPow2(x uint32) bool { return (x & (x - 1)) == 0 } | ||
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| // Pow2Image returns the given image, scaled to the smallest power-of-two | ||
| // dimensions larger or equal to the input dimensions. | ||
| // It preserves the image format and contents. | ||
| // | ||
| // This is useful if an image is to be used as an OpenGL texture. | ||
| // These often require image data to have power-of-two dimensions. | ||
| func Pow2Image(src image.Image) image.Image { | ||
| sb := src.Bounds() | ||
| w, h := uint32(sb.Dx()), uint32(sb.Dy()) | ||
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| if IsPow2(w) && IsPow2(h) { | ||
| return src // Nothing to do. | ||
| } | ||
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| rect := image.Rect(0, 0, int(Pow2(w)), int(Pow2(h))) | ||
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| switch src := src.(type) { | ||
| case *image.Alpha: | ||
| return copyImg(src, image.NewAlpha(rect)) | ||
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| case *image.Alpha16: | ||
| return copyImg(src, image.NewAlpha16(rect)) | ||
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| case *image.Gray: | ||
| return copyImg(src, image.NewGray(rect)) | ||
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| case *image.Gray16: | ||
| return copyImg(src, image.NewGray16(rect)) | ||
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| case *image.NRGBA: | ||
| return copyImg(src, image.NewNRGBA(rect)) | ||
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| case *image.NRGBA64: | ||
| return copyImg(src, image.NewNRGBA64(rect)) | ||
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| case *image.Paletted: | ||
| return copyImg(src, image.NewPaletted(rect, src.Palette)) | ||
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| case *image.RGBA: | ||
| return copyImg(src, image.NewRGBA(rect)) | ||
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| case *image.RGBA64: | ||
| return copyImg(src, image.NewRGBA64(rect)) | ||
| } | ||
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| panic(fmt.Sprintf("Unsupported image format: %T", src)) | ||
| } | ||
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| // Why the image.Image interface does not support this, | ||
| // I can never understand. | ||
| type copyable interface { | ||
| image.Image | ||
| Set(x, y int, clr color.Color) | ||
| } | ||
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| func copyImg(src, dst copyable) image.Image { | ||
| var x, y int | ||
| sb := src.Bounds() | ||
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| for y = 0; y < sb.Dy(); y++ { | ||
| for x = 0; x < sb.Dx(); x++ { | ||
| dst.Set(x, y, src.At(x, y)) | ||
| } | ||
| } | ||
|
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| return dst | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,43 @@ | ||
| // Copyright 2012 The go-gl Authors. All rights reserved. | ||
| // Use of this source code is governed by a BSD-style | ||
| // license that can be found in the LICENSE file. | ||
|
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| package gltext | ||
|
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| import ( | ||
| "testing" | ||
| ) | ||
|
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| func TestPow2(t *testing.T) { | ||
| tests := [...][2]uint32{ | ||
| {0, 0}, {1, 1}, {2, 2}, {3, 4}, | ||
| {4, 4}, {5, 8}, {6, 8}, {7, 8}, | ||
| {8, 8}, {9, 16}, {10, 16}, | ||
| } | ||
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| for i := range tests { | ||
| ret := Pow2(tests[i][0]) | ||
| if ret != tests[i][1] { | ||
| t.Fatalf("Pow2(%d): Want %d, Have %d", | ||
| tests[i][0], tests[i][1], ret) | ||
| } | ||
| } | ||
| } | ||
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| func TestIsPow2(t *testing.T) { | ||
| tests := [...]struct { | ||
| In uint32 | ||
| Out bool | ||
| }{ | ||
| {1, true}, {2, true}, {3, false}, {4, true}, {5, false}, | ||
| {6, false}, {7, false}, {8, true}, {9, false}, {10, false}, | ||
| } | ||
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| for i := range tests { | ||
| ret := IsPow2(tests[i].In) | ||
| if ret != tests[i].Out { | ||
| t.Fatalf("isPow2(%d): Want %d, Have %d", | ||
| tests[i].In, tests[i].Out, ret) | ||
| } | ||
| } | ||
| } |
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