support glBegin on GL_POINTS; fixes #793

4 files changed, 176 insertions, 6 deletions

diff --git a/src/library_gl.js b/src/library_gl.js
index 2a6ec92f..f68ce065 100644
--- a/src/library_gl.js
+++ b/src/library_gl.js
@@ -1393,7 +1393,7 @@ var LibraryGL = {
     tempData: null,
     indexData: null,
     vertexCounter: 0,
-    mode: 0,
+    mode: -1,
 
     rendererCache: null,
     rendererCacheItemTemplate: [null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null], // 16 nulls
@@ -1896,7 +1896,7 @@ var LibraryGL = {
           GL.immediate.lastVertex = first + count;
         }
         GL.immediate.flush(null, first);
-        GL.immediate.mode = 0;
+        GL.immediate.mode = -1;
       };
 
       _glDrawElements = function(mode, count, type, indices, start, end) { // start, end are given if we come from glDrawRangeElements
@@ -1915,7 +1915,7 @@ var LibraryGL = {
           GL.immediate.vertexData = {{{ makeHEAPView('F32', 'GL.immediate.vertexPointer', '(end ? GL.immediate.vertexPointer + (end+1)*GL.immediate.stride : TOTAL_MEMORY)') }}}; // XXX assuming float
         }
         GL.immediate.flush(count, 0, indices);
-        GL.immediate.mode = 0;
+        GL.immediate.mode = -1;
       };
     },
 
@@ -2060,12 +2060,12 @@ var LibraryGL = {
     GL.immediate.lastVertex = GL.immediate.vertexCounter / (GL.immediate.stride >> 2);
     GL.immediate.flush();
     GL.immediate.disableBeginEndClientAttributes();
-    GL.immediate.mode = 0;
+    GL.immediate.mode = -1;
   },
 
   glVertex3f: function(x, y, z) {
 #if ASSERTIONS
-    assert(GL.immediate.mode); // must be in begin/end
+    assert(GL.immediate.mode >= 0); // must be in begin/end
 #endif
     GL.immediate.vertexData[GL.immediate.vertexCounter++] = x;
     GL.immediate.vertexData[GL.immediate.vertexCounter++] = y;
@@ -2088,7 +2088,7 @@ var LibraryGL = {
 
   glTexCoord2i: function(u, v) {
 #if ASSERTIONS
-    assert(GL.immediate.mode); // must be in begin/end
+    assert(GL.immediate.mode >= 0); // must be in begin/end
 #endif
     GL.immediate.vertexData[GL.immediate.vertexCounter++] = u;
     GL.immediate.vertexData[GL.immediate.vertexCounter++] = v;
diff --git a/tests/glbegin_points.c b/tests/glbegin_points.c
new file mode 100644
index 00000000..b28cca4e
--- /dev/null
+++ b/tests/glbegin_points.c
@@ -0,0 +1,166 @@
+/*******************************************************************
+ *                                                                 *
+ *                        Using SDL With OpenGL                    *
+ *                                                                 *
+ *                    Tutorial by Kyle Foley (sdw)                 *
+ *                                                                 *
+ * http://gpwiki.org/index.php/SDL:Tutorials:Using_SDL_with_OpenGL *
+ *                                                                 *
+ *******************************************************************/
+
+/*
+THIS WORK, INCLUDING THE SOURCE CODE, DOCUMENTATION
+AND RELATED MEDIA AND DATA, IS PLACED INTO THE PUBLIC DOMAIN.
+
+THE ORIGINAL AUTHOR IS KYLE FOLEY.
+
+THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY
+OF ANY KIND, NOT EVEN THE IMPLIED WARRANTY OF
+MERCHANTABILITY. THE AUTHOR OF THIS SOFTWARE,
+ASSUMES _NO_ RESPONSIBILITY FOR ANY CONSEQUENCE
+RESULTING FROM THE USE, MODIFICATION, OR
+REDISTRIBUTION OF THIS SOFTWARE.
+*/
+
+#include "SDL/SDL.h"
+#include "SDL/SDL_image.h"
+#include "SDL/SDL_opengl.h"
+
+#include <stdio.h>
+#include <string.h>
+
+int main(int argc, char *argv[])
+{
+    SDL_Surface *screen;
+
+    // Slightly different SDL initialization
+    if ( SDL_Init(SDL_INIT_VIDEO) != 0 ) {
+        printf("Unable to initialize SDL: %s\n", SDL_GetError());
+        return 1;
+    }
+
+    SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 ); // *new*
+
+    screen = SDL_SetVideoMode( 640, 480, 16, SDL_OPENGL ); // *changed*
+    if ( !screen ) {
+        printf("Unable to set video mode: %s\n", SDL_GetError());
+        return 1;
+    }
+    
+    // Set the OpenGL state after creating the context with SDL_SetVideoMode
+
+    glClearColor( 0, 0, 0, 0 );
+    
+#if !EMSCRIPTEN
+    glEnable( GL_TEXTURE_2D ); // Need this to display a texture XXX unnecessary in OpenGL ES 2.0/WebGL
+#endif
+
+    glViewport( 0, 0, 640, 480 );
+
+    glMatrixMode( GL_PROJECTION );
+    GLfloat matrixData[] = { 2.0/640,        0,  0,  0,
+                                   0, -2.0/480,  0,  0,
+                                   0,        0, -1,  0,
+                                  -1,        1,  0,  1 };
+    glLoadMatrixf(matrixData); // test loadmatrix
+
+    glMatrixMode( GL_MODELVIEW );
+    glLoadIdentity();
+    
+    // Load the OpenGL texture
+
+    GLuint texture; // Texture object handle
+    SDL_Surface *surface; // Gives us the information to make the texture
+    
+    if ( (surface = IMG_Load("screenshot.png")) ) { 
+    
+        // Check that the image's width is a power of 2
+        if ( (surface->w & (surface->w - 1)) != 0 ) {
+            printf("warning: image.bmp's width is not a power of 2\n");
+        }
+    
+        // Also check if the height is a power of 2
+        if ( (surface->h & (surface->h - 1)) != 0 ) {
+            printf("warning: image.bmp's height is not a power of 2\n");
+        }
+    
+        // Have OpenGL generate a texture object handle for us
+        glGenTextures( 1, &texture );
+    
+        // Bind the texture object
+        glBindTexture( GL_TEXTURE_2D, texture );
+        
+        // Set the texture's stretching properties
+        glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
+        glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
+
+        //SDL_LockSurface(surface);
+
+        // Add some greyness
+        memset(surface->pixels, 0x66, surface->w*surface->h);
+
+        // Edit the texture object's image data using the information SDL_Surface gives us
+        glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, surface->w, surface->h, 0, 
+                      GL_RGBA, GL_UNSIGNED_BYTE, surface->pixels );
+
+        //SDL_UnlockSurface(surface);
+    } 
+    else {
+        printf("SDL could not load image.bmp: %s\n", SDL_GetError());
+        SDL_Quit();
+        return 1;
+    }    
+    
+    // Free the SDL_Surface only if it was successfully created
+    if ( surface ) { 
+        SDL_FreeSurface( surface );
+    }
+    
+    // Clear the screen before drawing
+    glClear( GL_COLOR_BUFFER_BIT );
+    
+    // Bind the texture to which subsequent calls refer to
+    glBindTexture( GL_TEXTURE_2D, texture );
+
+    // Use clientside vertex pointers to render two items
+    GLfloat vertexData[] = { 0, 0, 10, 10, // texture2, position2
+                             1, 0, 300, 10,
+                             1, 1, 300, 128,
+                             0, 1, 10, 128,
+                             0, 0.5, 410, 10,
+                             1, 0.5, 600, 10,
+                             1, 1, 630, 200,
+                             0.5, 1, 310, 250 };
+
+    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+    glTexCoordPointer(2, GL_FLOAT, 4*4, &vertexData[0]);
+    glEnableClientState(GL_VERTEX_ARRAY);
+    glVertexPointer(2, GL_FLOAT, 4*4, &vertexData[2]);
+
+    glDrawArrays(GL_POINTS, 0, 8);
+
+    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
+    glDisableClientState(GL_VERTEX_ARRAY);
+
+    // Render the last item using oldschool glBegin etc
+    glBegin( GL_POINTS );
+        glTexCoord2i( 0, 0 ); glVertex3f( 100, 300, 0 );
+        glTexCoord2i( 1, 0 ); glVertex2f( 300, 300 );
+        glTexCoord2i( 1, 1 ); { float vals[3] = { 300, 400, 0 }; glVertex3fv(vals); }
+        glTexCoord2i( 0, 1 ); { float vals[2] = { 500, 410 }; glVertex2fv(vals); }
+    glEnd();
+
+    SDL_GL_SwapBuffers();
+    
+#if !EMSCRIPTEN
+    // Wait for 3 seconds to give us a chance to see the image
+    SDL_Delay(3000);
+#endif
+
+    // Now we can delete the OpenGL texture and close down SDL
+    glDeleteTextures( 1, &texture );
+    
+    SDL_Quit();
+    
+    return 0;
+}
diff --git a/tests/glbegin_points.png b/tests/glbegin_points.png
new file mode 100644
index 00000000..57e15d29
--- /dev/null
+++ b/tests/glbegin_points.png
diff --git a/tests/runner.py b/tests/runner.py
index bef4001e..ee6b7c7c 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -10295,6 +10295,10 @@ elif 'browser' in str(sys.argv):
       Popen([PYTHON, EMCC, os.path.join(self.get_dir(), 'sdl_canvas_palette_2.c'), '-o', 'page.html', '--pre-js', 'pre.js']).communicate()
       self.run_browser('page.html', '')
 
+    def test_glbegin_points(self):
+      shutil.copyfile(path_from_root('tests', 'screenshot.png'), os.path.join(self.get_dir(), 'screenshot.png'))
+      self.btest('glbegin_points.c', reference='glbegin_points.png', args=['--preload-file', 'screenshot.png'])
+
     def test_s3tc(self):
       shutil.copyfile(path_from_root('tests', 'screenshot.dds'), os.path.join(self.get_dir(), 'screenshot.dds'))
       self.btest('s3tc.c', reference='s3tc.png', args=['--preload-file', 'screenshot.dds'])