Introduce float QImage formats and rendering

Useful for some HDR representations and HDR rendering.

Change-Id: If6e8a661faa3d2afdf17b6ed4d8ff5c5b2aeb30e
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

3 files changed, 85 insertions, 0 deletions

diff --git a/src/opengl/qopenglframebufferobject.cpp b/src/opengl/qopenglframebufferobject.cpp
index 78b192b630..aa1c396892 100644
--- a/src/opengl/qopenglframebufferobject.cpp
+++ b/src/opengl/qopenglframebufferobject.cpp
@@ -152,6 +152,25 @@ QT_BEGIN_NAMESPACE
 #define GL_DEPTH_STENCIL                  0x84F9
 #endif
 
+#ifndef GL_HALF_FLOAT
+#define GL_HALF_FLOAT                     0x140B
+#endif
+
+#ifndef GL_RGBA32F
+#define GL_RGBA32F                        0x8814
+#endif
+
+#ifndef GL_RGB32F
+#define GL_RGB32F                         0x8815
+#endif
+
+#ifndef GL_RGBA16F
+#define GL_RGBA16F                        0x881A
+#endif
+
+#ifndef GL_RGB16F
+#define GL_RGB16F                         0x881B
+#endif
 
 
 /*!
@@ -554,6 +573,8 @@ void QOpenGLFramebufferObjectPrivate::initTexture(int idx)
         pixelType = GL_UNSIGNED_INT_2_10_10_10_REV;
     else if (color.internalFormat == GL_RGB16  || color.internalFormat == GL_RGBA16)
         pixelType = GL_UNSIGNED_SHORT;
+    else if (color.internalFormat == GL_RGB16F  || color.internalFormat == GL_RGBA16F)
+        pixelType = GL_HALF_FLOAT;
 
     funcs.glTexImage2D(target, 0, color.internalFormat, color.size.width(), color.size.height(), 0,
                        GL_RGBA, pixelType, nullptr);
@@ -1379,6 +1400,21 @@ static inline QImage qt_gl_read_framebuffer_rgba16(const QSize &size, bool inclu
     return img;
 }
 
+static inline QImage qt_gl_read_framebuffer_rgba16f(const QSize &size, bool include_alpha, QOpenGLContext *context)
+{
+    // We assume OpenGL (ES) 3.0+ here.
+    QImage img(size, include_alpha ? QImage::Format_RGBA16FPx4_Premultiplied : QImage::Format_RGBX16FPx4);
+    context->functions()->glReadPixels(0, 0, size.width(), size.height(), GL_RGBA, GL_HALF_FLOAT, img.bits());
+    return img;
+}
+
+static inline QImage qt_gl_read_framebuffer_rgba32f(const QSize &size, bool include_alpha, QOpenGLContext *context)
+{
+    QImage img(size, include_alpha ? QImage::Format_RGBA32FPx4_Premultiplied : QImage::Format_RGBX32FPx4);
+    context->functions()->glReadPixels(0, 0, size.width(), size.height(), GL_RGBA, GL_FLOAT, img.bits());
+    return img;
+}
+
 static QImage qt_gl_read_framebuffer(const QSize &size, GLenum internal_format, bool include_alpha, bool flip)
 {
     QOpenGLContext *ctx = QOpenGLContext::currentContext();
@@ -1400,6 +1436,14 @@ static QImage qt_gl_read_framebuffer(const QSize &size, GLenum internal_format,
         return qt_gl_read_framebuffer_rgba16(size, false, ctx).mirrored(false, flip);
     case GL_RGBA16:
         return qt_gl_read_framebuffer_rgba16(size, include_alpha, ctx).mirrored(false, flip);
+    case GL_RGB16F:
+        return qt_gl_read_framebuffer_rgba16f(size, false, ctx).mirrored(false, flip);
+    case GL_RGBA16F:
+        return qt_gl_read_framebuffer_rgba16f(size, include_alpha, ctx).mirrored(false, flip);
+    case GL_RGB32F:
+        return qt_gl_read_framebuffer_rgba32f(size, false, ctx).mirrored(false, flip);
+    case GL_RGBA32F:
+        return qt_gl_read_framebuffer_rgba32f(size, include_alpha, ctx).mirrored(false, flip);
     case GL_RGBA:
     case GL_RGBA8:
     default:
diff --git a/src/opengl/qopenglpaintengine.cpp b/src/opengl/qopenglpaintengine.cpp
index 7da9bf143d..8606a2e7ef 100644
--- a/src/opengl/qopenglpaintengine.cpp
+++ b/src/opengl/qopenglpaintengine.cpp
@@ -1572,6 +1572,8 @@ void QOpenGL2PaintEngineEx::drawImage(const QRectF& dest, const QImage& image, c
     case QImage::Format_RGBA8888:
     case QImage::Format_ARGB32:
     case QImage::Format_RGBA64:
+    case QImage::Format_RGBA16FPx4:
+    case QImage::Format_RGBA32FPx4:
         d->shaderManager->setSrcPixelType(QOpenGLEngineShaderManager::NonPremultipliedImageSrc);
         bindOption = { };
         break;
diff --git a/src/opengl/qopengltextureuploader.cpp b/src/opengl/qopengltextureuploader.cpp
index 469ddc56c1..488baf32ad 100644
--- a/src/opengl/qopengltextureuploader.cpp
+++ b/src/opengl/qopengltextureuploader.cpp
@@ -45,6 +45,10 @@
 #include <private/qopenglcontext_p.h>
 #include <private/qopenglextensions_p.h>
 
+#ifndef GL_HALF_FLOAT
+#define GL_HALF_FLOAT                     0x140B
+#endif
+
 #ifndef GL_RED
 #define GL_RED                            0x1903
 #endif
@@ -81,6 +85,14 @@
 #define GL_UNSIGNED_INT_2_10_10_10_REV    0x8368
 #endif
 
+#ifndef GL_RGBA16F
+#define GL_RGBA16F                        0x881A
+#endif
+
+#ifndef GL_RGBA32F
+#define GL_RGBA32F                        0x8814
+#endif
+
 #ifndef GL_TEXTURE_SWIZZLE_R
 #define GL_TEXTURE_SWIZZLE_R              0x8E42
 #endif
@@ -236,6 +248,25 @@ qsizetype QOpenGLTextureUploader::textureImage(GLenum target, const QImage &imag
         pixelType = GL_UNSIGNED_SHORT;
         targetFormat =  image.format();
         break;
+    case QImage::Format_RGBX16FPx4:
+    case QImage::Format_RGBA16FPx4:
+    case QImage::Format_RGBA16FPx4_Premultiplied:
+        if (context->format().majorVersion() >= 3) {
+            externalFormat = GL_RGBA;
+            internalFormat = GL_RGBA16F;
+            pixelType = GL_HALF_FLOAT;
+            targetFormat =  image.format();
+        }
+        break;
+    case QImage::Format_RGBX32FPx4:
+    case QImage::Format_RGBA32FPx4:
+    case QImage::Format_RGBA32FPx4_Premultiplied:
+        externalFormat = internalFormat = GL_RGBA;
+        if (context->format().majorVersion() >= 3)
+            internalFormat = GL_RGBA32F;
+        pixelType = GL_FLOAT;
+        targetFormat =  image.format();
+        break;
     case QImage::Format_Indexed8:
         if (sRgbBinding) {
             // Always needs conversion
@@ -333,6 +364,10 @@ qsizetype QOpenGLTextureUploader::textureImage(GLenum target, const QImage &imag
             targetFormat = QImage::Format_RGBA8888_Premultiplied;
         else if (targetFormat == QImage::Format_RGBA64)
             targetFormat = QImage::Format_RGBA64_Premultiplied;
+        else if (targetFormat == QImage::Format_RGBA16FPx4)
+            targetFormat = QImage::Format_RGBA16FPx4_Premultiplied;
+        else if (targetFormat == QImage::Format_RGBA32FPx4)
+            targetFormat = QImage::Format_RGBA32FPx4_Premultiplied;
     } else {
         if (targetFormat == QImage::Format_ARGB32_Premultiplied)
             targetFormat = QImage::Format_ARGB32;
@@ -340,6 +375,10 @@ qsizetype QOpenGLTextureUploader::textureImage(GLenum target, const QImage &imag
             targetFormat = QImage::Format_RGBA8888;
         else if (targetFormat == QImage::Format_RGBA64_Premultiplied)
             targetFormat = QImage::Format_RGBA64;
+        else if (targetFormat == QImage::Format_RGBA16FPx4_Premultiplied)
+            targetFormat = QImage::Format_RGBA16FPx4;
+        else if (targetFormat == QImage::Format_RGBA32FPx4_Premultiplied)
+            targetFormat = QImage::Format_RGBA32FPx4;
     }
 
     if (sRgbBinding) {