testdyngles is exactly what it sounds like -- a version of testdyngl …

…that uses OpenGL ES calls instead of OpenGL. Was necessary to create because glOrtho is called glOrthof in OpenGL ES, and OpenGL ES doesn't have glBegin() type semantics for specifying geometry.
libsdl-org · Aug 15, 2008 · ed749cb · ed749cb
1 parent a82894a
commit ed749cb
Showing 1 changed file with 211 additions and 0 deletions.
diff --git a/test/testdyngles.c b/test/testdyngles.c
@@ -0,0 +1,211 @@
+/*
+ * Small SDL example to demonstrate dynamically loading 
+ * OpenGL lib and functions
+ *
+ * (FYI it was supposed to look like snow in the wind or something...)
+ *
+ * Compile with :
+ * gcc testdyngl.c `sdl-config --libs --cflags` -o testdyngl -DHAVE_OPENGL
+ *
+ * You can specify a different OpenGL lib on the command line, i.e. :
+ * ./testdyngl  /usr/X11R6/lib/libGL.so.1.2
+ * or
+ * ./testdyngl  /usr/lib/libGL.so.1.0.4496
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "SDL.h"
+
+#ifdef __IPHONEOS__
+#define HAVE_OPENGLES
+#endif
+
+#ifdef HAVE_OPENGLES
+
+#include "SDL_opengles.h"
+
+/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
+static void
+quit(int rc)
+{
+    SDL_Quit();
+    exit(rc);
+}
+
+void *
+get_funcaddr(const char *p)
+{
+    void *f = SDL_GL_GetProcAddress(p);
+    if (f) {
+        return f;
+    } else {
+        printf("Unable to get function pointer for %s\n", p);
+        quit(1);
+    }
+    return NULL;
+}
+
+typedef struct
+{
+    //void (APIENTRY * glBegin) (GLenum);
+    //void (APIENTRY * glEnd) ();
+    //void (APIENTRY * glVertex3f) (GLfloat, GLfloat, GLfloat);
+
+	void (APIENTRY *glEnableClientState)(GLenum array);
+	void (APIENTRY *glVertexPointer)(GLint size, GLenum type, GLsizei stride, const GLvoid *pointer);
+	void (APIENTRY *glDrawArrays)(GLenum mode, GLint first, GLsizei count);
+
+
+    void (APIENTRY * glClearColor) (GLfloat, GLfloat, GLfloat, GLfloat);
+    void (APIENTRY * glClear) (GLbitfield);
+    void (APIENTRY * glDisable) (GLenum);
+    void (APIENTRY * glEnable) (GLenum);
+    void (APIENTRY * glColor4ub) (GLubyte, GLubyte, GLubyte, GLubyte);
+    void (APIENTRY * glPointSize) (GLfloat);
+    void (APIENTRY * glHint) (GLenum, GLenum);
+    void (APIENTRY * glBlendFunc) (GLenum, GLenum);
+    void (APIENTRY * glMatrixMode) (GLenum);
+    void (APIENTRY * glLoadIdentity) ();
+    void (APIENTRY * glOrthof) (GLfloat, GLfloat, GLfloat, GLfloat,
+                               GLfloat, GLfloat);
+    void (APIENTRY * glRotatef) (GLfloat, GLfloat, GLfloat, GLfloat);
+    void (APIENTRY * glViewport) (GLint, GLint, GLsizei, GLsizei);
+    void (APIENTRY * glFogf) (GLenum, GLfloat);
+}
+glfuncs;
+
+void
+init_glfuncs(glfuncs * f)
+{
+	f->glEnableClientState = get_funcaddr("glEnableClientState");
+	f->glVertexPointer = get_funcaddr("glVertexPointer");
+	f->glDrawArrays = get_funcaddr("glDrawArrays");
+	f->glClearColor = get_funcaddr("glClearColor");
+    f->glClear = get_funcaddr("glClear");
+    f->glDisable = get_funcaddr("glDisable");
+    f->glEnable = get_funcaddr("glEnable");
+    f->glColor4ub = get_funcaddr("glColor4ub");
+    f->glPointSize = get_funcaddr("glPointSize");
+    f->glHint = get_funcaddr("glHint");
+    f->glBlendFunc = get_funcaddr("glBlendFunc");
+    f->glMatrixMode = get_funcaddr("glMatrixMode");
+    f->glLoadIdentity = get_funcaddr("glLoadIdentity");
+    f->glOrthof = get_funcaddr("glOrthof");
+    f->glRotatef = get_funcaddr("glRotatef");
+    f->glViewport = get_funcaddr("glViewport");
+    f->glFogf = get_funcaddr("glFogf");
+}
+
+#define NB_PIXELS 1000
+
+int
+main(int argc, char *argv[])
+{
+    glfuncs f;
+    int i;
+    SDL_Event event;
+    int done = 0;
+    GLfloat pixels[NB_PIXELS * 3];
+    const char *gl_library = NULL;      /* Use the default GL library */
+
+	int video_w, video_h;
+
+	/* you may want to change these according to the platform */
+	video_w = 320; 
+	video_h = 480;
+
+    if (argv[1]) {
+        gl_library = argv[1];
+    }
+
+    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
+        printf("Unable to init SDL : %s\n", SDL_GetError());
+        return (1);
+    }
+
+    if (SDL_GL_LoadLibrary(gl_library) < 0) {
+        printf("Unable to dynamically open GL lib : %s\n", SDL_GetError());
+        quit(1);
+    }
+
+    if (SDL_SetVideoMode(video_h, video_w, 0, SDL_OPENGL) == NULL) {
+        printf("Unable to open video mode : %s\n", SDL_GetError());
+        quit(1);
+    }
+
+    /* Set the window manager title bar */
+    SDL_WM_SetCaption("SDL Dynamic OpenGL Loading Test", "testdyngl");
+
+    init_glfuncs(&f);
+
+    for (i = 0; i < NB_PIXELS; i++) {
+        pixels[3 * i] = rand() % 250 - 125;
+        pixels[3 * i + 1] = rand() % 250 - 125;
+        pixels[3 * i + 2] = rand() % 250 - 125;
+    }
+
+    f.glViewport(0, 0, video_w, video_h);
+
+    f.glMatrixMode(GL_PROJECTION);
+    f.glLoadIdentity();
+    f.glOrthof(-100, 100, -100, 100, -500, 500);
+
+    f.glMatrixMode(GL_MODELVIEW);
+    f.glLoadIdentity();
+
+    f.glEnable(GL_DEPTH_TEST);
+    f.glDisable(GL_TEXTURE_2D);
+    f.glEnable(GL_BLEND);
+    f.glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+    f.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+    f.glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    f.glEnable(GL_POINT_SMOOTH);
+    f.glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);
+    f.glPointSize(5.0f);
+    f.glEnable(GL_FOG);
+    f.glFogf(GL_FOG_START, -500);
+    f.glFogf(GL_FOG_END, 500);
+    f.glFogf(GL_FOG_DENSITY, 0.005);
+
+    do {
+        f.glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+        f.glRotatef(2.0, 1.0, 1.0, 1.0);
+        f.glRotatef(1.0, 0.0, 1.0, 1.0);
+
+        f.glColor4ub(255, 255, 255, 255);
+
+		f.glEnableClientState(GL_VERTEX_ARRAY);
+		f.glVertexPointer(3, GL_FLOAT, 0, pixels);
+		f.glDrawArrays(GL_POINTS, 0, NB_PIXELS);
+
+        SDL_GL_SwapBuffers();
+
+        while (SDL_PollEvent(&event)) {
+            if (event.type == SDL_KEYDOWN)
+                done = 1;
+        }
+
+        SDL_Delay(20);
+    }
+    while (!done);
+
+    SDL_Quit();
+    return 0;
+}
+
+#else /* HAVE_OPENGLES */
+
+int
+main(int argc, char *argv[])
+{
+    printf("No OpenGL support on this system\n");
+    return 1;
+}
+
+#endif /* HAVE_OPENGLES */