Port the textures example to OpenGL/ES 2.0

Reviewed-by: trustme

2 files changed, 88 insertions, 32 deletions

diff --git a/examples/opengl/textures/glwidget.cpp b/examples/opengl/textures/glwidget.cpp
index 024133b..6efd31a 100644
--- a/examples/opengl/textures/glwidget.cpp
+++ b/examples/opengl/textures/glwidget.cpp
@@ -44,16 +44,6 @@
 
 #include "glwidget.h"
 
-class CubeObject
-{
-public:
-    GLuint textures[6];
-    QVector<QVector3D> vertices;
-    QVector<QVector2D> texCoords;
-
-    void draw();
-};
-
 GLWidget::GLWidget(QWidget *parent, QGLWidget *shareWidget)
     : QGLWidget(parent, shareWidget)
 {
@@ -61,12 +51,13 @@ GLWidget::GLWidget(QWidget *parent, QGLWidget *shareWidget)
     xRot = 0;
     yRot = 0;
     zRot = 0;
-    cube = 0;
+#ifdef QT_OPENGL_ES_2
+    program = 0;
+#endif
 }
 
 GLWidget::~GLWidget()
 {
-    delete cube;
 }
 
 QSize GLWidget::minimumSizeHint() const
@@ -99,19 +90,90 @@ void GLWidget::initializeGL()
 
     glEnable(GL_DEPTH_TEST);
     glEnable(GL_CULL_FACE);
+#ifndef QT_OPENGL_ES_2
     glEnable(GL_TEXTURE_2D);
+#endif
+
+#ifdef QT_OPENGL_ES_2
+
+#define PROGRAM_VERTEX_ATTRIBUTE 0
+#define PROGRAM_TEXCOORD_ATTRIBUTE 1
+
+    QGLShader *vshader = new QGLShader(QGLShader::VertexShader, this);
+    const char *vsrc =
+        "attribute highp vec4 vertex;\n"
+        "attribute mediump vec4 texCoord;\n"
+        "varying mediump vec4 texc;\n"
+        "uniform mediump mat4 matrix;\n"
+        "void main(void)\n"
+        "{\n"
+        "    gl_Position = matrix * vertex;\n"
+        "    texc = texCoord;\n"
+        "}\n";
+    vshader->compile(vsrc);
+
+    QGLShader *fshader = new QGLShader(QGLShader::FragmentShader, this);
+    const char *fsrc =
+        "uniform sampler2D texture;\n"
+        "varying mediump vec4 texc;\n"
+        "void main(void)\n"
+        "{\n"
+        "    gl_FragColor = texture2D(texture, texc.st);\n"
+        "}\n";
+    fshader->compile(fsrc);
+
+    program = new QGLShaderProgram(this);
+    program->addShader(vshader);
+    program->addShader(fshader);
+    program->bindAttributeLocation("vertex", PROGRAM_VERTEX_ATTRIBUTE);
+    program->bindAttributeLocation("texCoord", PROGRAM_TEXCOORD_ATTRIBUTE);
+    program->link();
+
+    program->enable();
+    program->setUniformValue("texture", 0);
+
+#endif
 }
 
 void GLWidget::paintGL()
 {
     qglClearColor(clearColor);
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+#if !defined(QT_OPENGL_ES_2)
+
     glLoadIdentity();
     glTranslatef(0.0f, 0.0f, -10.0f);
     glRotatef(xRot / 16.0f, 1.0f, 0.0f, 0.0f);
     glRotatef(yRot / 16.0f, 0.0f, 1.0f, 0.0f);
     glRotatef(zRot / 16.0f, 0.0f, 0.0f, 1.0f);
-    cube->draw();
+
+    glVertexPointer(3, GL_FLOAT, 0, vertices.constData());
+    glTexCoordPointer(2, GL_FLOAT, 0, texCoords.constData());
+    glEnableClientState(GL_VERTEX_ARRAY);
+    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+
+#else
+
+    QMatrix4x4 m;
+    m.ortho(-0.5f, +0.5f, +0.5f, -0.5f, 4.0f, 15.0f);
+    m.translate(0.0f, 0.0f, -10.0f);
+    m.rotate(xRot / 16.0f, 1.0f, 0.0f, 0.0f);
+    m.rotate(yRot / 16.0f, 0.0f, 1.0f, 0.0f);
+    m.rotate(zRot / 16.0f, 0.0f, 0.0f, 1.0f);
+
+    program->setUniformValue("matrix", m);
+    program->setAttributeArray
+        (PROGRAM_VERTEX_ATTRIBUTE, vertices.constData());
+    program->setAttributeArray
+        (PROGRAM_TEXCOORD_ATTRIBUTE, texCoords.constData());
+
+#endif
+
+    for (int i = 0; i < 6; ++i) {
+        glBindTexture(GL_TEXTURE_2D, textures[i]);
+        glDrawArrays(GL_TRIANGLE_FAN, i * 4, 4);
+    }
 }
 
 void GLWidget::resizeGL(int width, int height)
@@ -119,6 +181,7 @@ void GLWidget::resizeGL(int width, int height)
     int side = qMin(width, height);
     glViewport((width - side) / 2, (height - side) / 2, side, side);
 
+#if !defined(QT_OPENGL_ES_2)
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
 #ifndef QT_OPENGL_ES
@@ -127,6 +190,7 @@ void GLWidget::resizeGL(int width, int height)
     glOrthof(-0.5, +0.5, +0.5, -0.5, 4.0, 15.0);
 #endif
     glMatrixMode(GL_MODELVIEW);
+#endif
 }
 
 void GLWidget::mousePressEvent(QMouseEvent *event)
@@ -163,32 +227,18 @@ void GLWidget::makeObject()
         { { -1, -1, +1 }, { +1, -1, +1 }, { +1, +1, +1 }, { -1, +1, +1 } }
     };
 
-    cube = new CubeObject();
-
     for (int j=0; j < 6; ++j) {
-        cube->textures[j] = bindTexture
+        textures[j] = bindTexture
             (QPixmap(QString(":/images/side%1.png").arg(j + 1)), GL_TEXTURE_2D);
     }
 
     for (int i = 0; i < 6; ++i) {
         for (int j = 0; j < 4; ++j) {
-            cube->texCoords.append
+            texCoords.append
                 (QVector2D(j == 0 || j == 3, j == 0 || j == 1));
-            cube->vertices.append
+            vertices.append
                 (QVector3D(0.2 * coords[i][j][0], 0.2 * coords[i][j][1],
                            0.2 * coords[i][j][2]));
         }
     }
 }
-
-void CubeObject::draw()
-{
-    glVertexPointer(3, GL_FLOAT, 0, vertices.constData());
-    glTexCoordPointer(2, GL_FLOAT, 0, texCoords.constData());
-    glEnableClientState(GL_VERTEX_ARRAY);
-    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
-    for (int i = 0; i < 6; ++i) {
-        glBindTexture(GL_TEXTURE_2D, textures[i]);
-        glDrawArrays(GL_TRIANGLE_FAN, i * 4, 4);
-    }
-}
diff --git a/examples/opengl/textures/glwidget.h b/examples/opengl/textures/glwidget.h
index 46507ce..4dcff3b 100644
--- a/examples/opengl/textures/glwidget.h
+++ b/examples/opengl/textures/glwidget.h
@@ -42,9 +42,10 @@
 #ifndef GLWIDGET_H
 #define GLWIDGET_H
 
+#include <QtGui>
 #include <QGLWidget>
 
-class CubeObject;
+class QGLShaderProgram;
 
 class GLWidget : public QGLWidget
 {
@@ -78,7 +79,12 @@ private:
     int xRot;
     int yRot;
     int zRot;
-    CubeObject *cube;
+    GLuint textures[6];
+    QVector<QVector3D> vertices;
+    QVector<QVector2D> texCoords;
+#ifdef QT_OPENGL_ES_2
+    QGLShaderProgram *program;
+#endif
 };
 
 #endif