Added support for OpenGL V3 and higher.

On the X11/MSWindows platforms, this requires external installation of the GLEW library.
This fixes STR#3198 and STR#3257.
Added two new examples programs.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10876 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

1 files changed, 199 insertions, 0 deletions

diff --git a/examples/OpenGL3-glut-test.cxx b/examples/OpenGL3-glut-test.cxx
new file mode 100644
index 000000000..f455eaf56
--- /dev/null
+++ b/examples/OpenGL3-glut-test.cxx
@@ -0,0 +1,199 @@
+#include <stdio.h>
+#if defined(__APPLE__)
+#  include <OpenGL/gl3.h> // defines OpenGL 3.0+ functions
+#else
+#  if defined(WIN32)
+#    define GLEW_STATIC 1
+#  endif
+#  include <GL/glew.h>
+#endif
+#include <FL/glut.H>
+
+
+// Globals
+// Real programs don't use globals :-D
+// Data would normally be read from files
+GLfloat vertices[] = {	-1.0f,0.0f,0.0f,
+  0.0f,1.0f,0.0f,
+  0.0f,0.0f,0.0f };
+GLfloat colours[] = {	1.0f, 0.0f, 0.0f,
+  0.0f, 1.0f, 0.0f,
+  0.0f, 0.0f, 1.0f };
+GLfloat vertices2[] = {	0.0f,0.0f,0.0f,
+  0.0f,-1.0f,0.0f,
+  1.0f,0.0f,0.0f };
+
+// two vertex array objects, one for each object drawn
+unsigned int vertexArrayObjID[2];
+// three vertex buffer objects in this example
+unsigned int vertexBufferObjID[3];
+
+
+void printShaderInfoLog(GLint shader)
+{
+  int infoLogLen = 0;
+  GLchar *infoLog;
+  
+  glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLogLen);
+  if (infoLogLen > 0)
+  {
+    infoLog = new GLchar[infoLogLen];
+    // error check for fail to allocate memory omitted
+    glGetShaderInfoLog(shader,infoLogLen, NULL, infoLog);
+    fprintf(stderr, "InfoLog:\n%s\n", infoLog);
+    delete [] infoLog;
+  }
+}
+
+
+void init(void)
+{
+  // Would load objects from file here - but using globals in this example
+  
+  // Allocate Vertex Array Objects
+  glGenVertexArrays(2, &vertexArrayObjID[0]);
+  // Setup first Vertex Array Object
+  glBindVertexArray(vertexArrayObjID[0]);
+  glGenBuffers(2, vertexBufferObjID);
+  
+  // VBO for vertex data
+  glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObjID[0]);
+  glBufferData(GL_ARRAY_BUFFER, 9*sizeof(GLfloat), vertices, GL_STATIC_DRAW);
+  glVertexAttribPointer((GLuint)0, 3, GL_FLOAT, GL_FALSE, 0, 0);
+  glEnableVertexAttribArray(0);
+  
+  // VBO for colour data
+  glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObjID[1]);
+  glBufferData(GL_ARRAY_BUFFER, 9*sizeof(GLfloat), colours, GL_STATIC_DRAW);
+  glVertexAttribPointer((GLuint)1, 3, GL_FLOAT, GL_FALSE, 0, 0);
+  glEnableVertexAttribArray(1);
+  
+  // Setup second Vertex Array Object
+  glBindVertexArray(vertexArrayObjID[1]);
+  glGenBuffers(1, &vertexBufferObjID[2]);
+  
+  // VBO for vertex data
+  glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObjID[2]);
+  glBufferData(GL_ARRAY_BUFFER, 9*sizeof(GLfloat), vertices2, GL_STATIC_DRAW);
+  glVertexAttribPointer((GLuint)0, 3, GL_FLOAT, GL_FALSE, 0, 0);
+  glEnableVertexAttribArray(0);
+  
+  glBindVertexArray(0);
+}
+
+
+void initShaders(void)
+{
+  GLuint p, f, v;
+  glClearColor (1.0, 1.0, 1.0, 0.0);
+  
+  v = glCreateShader(GL_VERTEX_SHADER);
+  f = glCreateShader(GL_FRAGMENT_SHADER);
+  
+#ifdef __APPLE__
+#define SHADING_LANG_VERS "140"
+#else
+#define SHADING_LANG_VERS "130"
+#endif
+  // load shaders
+  const char *vv = "#version "SHADING_LANG_VERS"\n\
+  in  vec3 in_Position;\
+  in  vec3 in_Color;\
+  out vec3 ex_Color;\
+  void main(void)\
+  {\
+    ex_Color = in_Color;\
+    gl_Position = vec4(in_Position, 1.0);\
+  }";
+  
+  const char *ff = "#version "SHADING_LANG_VERS"\n\
+  precision highp float;\
+  in  vec3 ex_Color;\
+  out vec4 out_Color;\
+  void main(void)\
+  {\
+    out_Color = vec4(ex_Color,1.0);\
+  }";
+  
+  glShaderSource(v, 1, &vv,NULL);
+  glShaderSource(f, 1, &ff,NULL);
+  
+  GLint compiled;
+  
+  glCompileShader(v);
+  glGetShaderiv(v, GL_COMPILE_STATUS, &compiled);
+  if (!compiled)
+  {
+    fprintf(stderr, "Vertex shader not compiled.\n");
+    printShaderInfoLog(v);
+  }
+  
+  glCompileShader(f);
+  glGetShaderiv(f, GL_COMPILE_STATUS, &compiled);
+  if (!compiled)
+  {
+    fprintf(stderr, "Fragment shader not compiled.\n");
+    printShaderInfoLog(f);
+  }
+  
+  p = glCreateProgram();
+  
+  glAttachShader(p,v);
+  glAttachShader(p,f);
+  glBindAttribLocation(p,0, "in_Position");
+  glBindAttribLocation(p,1, "in_Color");
+
+  glLinkProgram(p);
+  glGetProgramiv(p, GL_LINK_STATUS, &compiled);
+  if (compiled != GL_TRUE) {
+    GLchar *infoLog; GLint length;
+    glGetProgramiv(p, GL_INFO_LOG_LENGTH, &length);
+    infoLog = new GLchar[length];
+    glGetProgramInfoLog(p, length, NULL, infoLog);
+    fprintf(stderr, "Link log=%s\n", infoLog);
+    delete[] infoLog;
+  }
+  glUseProgram(p);
+}
+
+
+void display(void)
+{
+  // clear the screen
+  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+  
+  glBindVertexArray(vertexArrayObjID[0]);	// First VAO
+  glDrawArrays(GL_TRIANGLES, 0, 3);	// draw first object
+  
+  glBindVertexArray(vertexArrayObjID[1]);		// select second VAO
+  glVertexAttrib3f((GLuint)1, 1.0, 0.0, 0.0); // set constant color attribute
+  glDrawArrays(GL_TRIANGLES, 0, 3);	// draw second object
+ }
+
+
+int main (int argc, char* argv[])
+{
+  Fl::use_high_res_GL(true);
+  glutInit(&argc, argv);
+  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | FL_OPENGL3);
+  glutInitWindowSize(400,400);
+  glutCreateWindow("Triangle Test");
+#ifndef __APPLE__
+  GLenum err = glewInit(); // defines pters to functions of OpenGL V 1.2 and above
+  if (err) Fl::error("glewInit() failed returning %u", err);
+  fprintf(stderr, "Status: Using GLEW %s\n", glewGetString(GLEW_VERSION));
+#endif
+  int gl_version_major;
+  const char *glv = (const char*)glGetString(GL_VERSION);
+  fprintf(stderr, "OpenGL version %s supported\n", glv);
+  sscanf(glv, "%d", &gl_version_major);
+  if (gl_version_major < 3) {
+    fprintf(stderr, "\nThis platform does not support OpenGL V3\n\n");
+    exit(1);
+  }
+  initShaders();
+  init();
+  glutDisplayFunc(display);
+  glutMainLoop();
+  return 0;
+}