From 35110d72c631bfc8d76e1e032dc6c7fa10c7d87a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fredrik=20H=C3=B6glund?= <fredrik@kde.org>
Date: Sat, 13 Dec 2014 14:39:46 +0100
Subject: [PATCH] Avoid converting images in GLTexture when possible

Don't convert the QImage when the image format can be specified as
a format/type combination to glTex(Sub)Image().
---
 libkwineffects/kwingltexture.cpp | 66 +++++++++++++++++++++++++++++---
 1 file changed, 60 insertions(+), 6 deletions(-)

diff --git a/libkwineffects/kwingltexture.cpp b/libkwineffects/kwingltexture.cpp
index a84fddcef6..5ce633a41f 100644
--- a/libkwineffects/kwingltexture.cpp
+++ b/libkwineffects/kwingltexture.cpp
@@ -75,7 +75,6 @@ GLTexture::GLTexture(const QImage& image, GLenum target)
         return;
 
     d->m_target = target;
-    d->m_internalFormat = GL_RGBA8;
 
     if (d->m_target != GL_TEXTURE_RECTANGLE_ARB) {
         d->m_scale.setWidth(1.0 / image.width());
@@ -96,19 +95,74 @@ GLTexture::GLTexture(const QImage& image, GLenum target)
     bind();
 
     if (!GLPlatform::instance()->isGLES()) {
-        const QImage im = image.convertToFormat(QImage::Format_ARGB32_Premultiplied);
+        // Note: Blending is set up to expect premultiplied data, so non-premultiplied
+        //       formats must always be converted.
+        struct {
+            GLenum internalFormat;
+            GLenum format;
+            GLenum type;
+        } static const table[] = {
+            { 0,           0,       0                              }, // QImage::Format_Invalid
+            { 0,           0,       0                              }, // QImage::Format_Mono
+            { 0,           0,       0                              }, // QImage::Format_MonoLSB
+            { GL_R8,       GL_RED,  GL_UNSIGNED_BYTE               }, // QImage::Format_Indexed8
+            { GL_RGB8,     GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV    }, // QImage::Format_RGB32
+            { 0,           0,       0                              }, // QImage::Format_ARGB32
+            { GL_RGBA8,    GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV    }, // QImage::Format_ARGB32_Premultiplied
+            { GL_RGB8,     GL_BGR,  GL_UNSIGNED_SHORT_5_6_5_REV    }, // QImage::Format_RGB16
+            { 0,           0,       0                              }, // QImage::Format_ARGB8565_Premultiplied
+            { 0,           0,       0                              }, // QImage::Format_RGB666
+            { GL_RGB5,     GL_BGRA, GL_UNSIGNED_SHORT_1_5_5_5_REV  }, // QImage::Format_RGB555
+            { 0,           0,       0                              }, // QImage::Format_ARGB8555_Premultiplied
+            { GL_RGB8,     GL_RGB,  GL_UNSIGNED_BYTE               }, // QImage::Format_RGB888
+            { GL_RGB4,     GL_BGRA, GL_UNSIGNED_SHORT_4_4_4_4_REV  }, // QImage::Format_RGB444
+            { GL_RGBA4,    GL_BGRA, GL_UNSIGNED_SHORT_4_4_4_4_REV  }, // QImage::Format_ARGB4444_Premultiplied
+            { GL_RGB8,     GL_RGBA, GL_UNSIGNED_BYTE               }, // QImage::Format_RGBX8888
+            { 0,           0,       0                              }, // QImage::Format_RGBA8888
+            { GL_RGBA8,    GL_RGBA, GL_UNSIGNED_BYTE               }, // QImage::Format_RGBA8888_Premultiplied
+#if QT_VERSION >= QT_VERSION_CHECK(5, 4, 0)
+            { GL_RGB10,    GL_RGBA, GL_UNSIGNED_INT_2_10_10_10_REV }, // QImage::Format_BGR30
+            { GL_RGB10_A2, GL_RGBA, GL_UNSIGNED_INT_2_10_10_10_REV }, // QImage::Format_A2BGR30_Premultiplied
+            { GL_RGB10,    GL_BGRA, GL_UNSIGNED_INT_2_10_10_10_REV }, // QImage::Format_RGB30
+            { GL_RGB10_A2, GL_BGRA, GL_UNSIGNED_INT_2_10_10_10_REV }, // QImage::Format_A2RGB30_Premultiplied
+#endif
+        };
+
+        QImage im;
+        GLenum internalFormat;
+        GLenum format;
+        GLenum type;
+
+        const QImage::Format index = image.format();
+
+        if (index < sizeof(table) / sizeof(table[0]) && table[index].internalFormat &&
+            !(index == QImage::Format_Indexed8 && image.colorCount() > 0)) {
+            internalFormat = table[index].internalFormat;
+            format = table[index].format;
+            type = table[index].type;
+            im = image;
+        } else {
+            im = image.convertToFormat(QImage::Format_ARGB32_Premultiplied);
+            internalFormat = GL_RGBA8;
+            format = GL_BGRA;
+            type = GL_UNSIGNED_INT_8_8_8_8_REV;
+        }
+
+        d->m_internalFormat = internalFormat;
 
         if (d->s_supportsTextureStorage) {
-            glTexStorage2D(d->m_target, 1, GL_RGBA8, im.width(), im.height());
+            glTexStorage2D(d->m_target, 1, internalFormat, im.width(), im.height());
             glTexSubImage2D(d->m_target, 0, 0, 0, im.width(), im.height(),
-                            GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, im.bits());
+                            format, type, im.bits());
             d->m_immutable = true;
         } else {
             glTexParameteri(d->m_target, GL_TEXTURE_MAX_LEVEL, d->m_mipLevels - 1);
-            glTexImage2D(d->m_target, 0, GL_RGBA8, im.width(), im.height(), 0,
-                         GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, im.bits());
+            glTexImage2D(d->m_target, 0, internalFormat, im.width(), im.height(), 0,
+                         format, type, im.bits());
         }
     } else {
+        d->m_internalFormat = GL_RGBA8;
+
         if (d->s_supportsARGB32) {
             const QImage im = image.convertToFormat(QImage::Format_ARGB32_Premultiplied);
             glTexImage2D(d->m_target, 0, GL_BGRA_EXT, im.width(), im.height(),