Initialize the projection and modelview matrices to identity

This is required by the spec.  Without this change, the testcase in this
patch merely renders the background, and the box in the upper right
corner will not get rendered at all.

3 files changed, 134 insertions, 0 deletions

diff --git a/src/library_gl.js b/src/library_gl.js
index 10c4374c..1b6ec5c0 100644
--- a/src/library_gl.js
+++ b/src/library_gl.js
@@ -1684,7 +1684,9 @@ var LibraryGL = {
       // Initialize matrix library
 
       GL.immediate.matrix['m'] = GL.immediate.matrix.lib.mat4.create();
+      GL.immediate.matrix.lib.mat4.identity(GL.immediate.matrix['m']);
       GL.immediate.matrix['p'] = GL.immediate.matrix.lib.mat4.create();
+      GL.immediate.matrix.lib.mat4.identity(GL.immediate.matrix['p']);
       for (var i = 0; i < GL.immediate.MAX_TEXTURES; i++) {
         GL.immediate.matrix['t' + i] = GL.immediate.matrix.lib.mat4.create();
       }
diff --git a/tests/gl_matrix_identity.c b/tests/gl_matrix_identity.c
new file mode 100644
index 00000000..98b1c21f
--- /dev/null
+++ b/tests/gl_matrix_identity.c
@@ -0,0 +1,129 @@
+/*
+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.
+*/
+
+#if !EMSCRIPTEN
+#define USE_GLEW 1
+#endif
+
+#if USE_GLEW
+#include "GL/glew.h"
+#endif
+
+#include "SDL/SDL.h"
+#if !USE_GLEW
+#include "SDL/SDL_opengl.h"
+#endif
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+void verify() {
+  int width = 640, height = 480;
+  unsigned char *data = (unsigned char*)malloc(width*height*4);
+  glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, data);
+  int sum = 0;
+  for (int x = 0; x < width*height*4; x++) {
+    if (x % 4 != 3) sum += x * data[x];
+  }
+#if EMSCRIPTEN
+  int result = sum;
+  REPORT_RESULT();
+#endif
+}
+
+int main(int argc, char *argv[])
+{
+    SDL_Surface *screen;
+    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 );
+    screen = SDL_SetVideoMode( 640, 480, 24, SDL_OPENGL );
+    if ( !screen ) {
+        printf("Unable to set video mode: %s\n", SDL_GetError());
+        return 1;
+    }
+
+    // Create a texture
+
+    GLuint texture;
+    glGenTextures( 1, &texture );
+    glBindTexture( GL_TEXTURE_2D, texture );
+    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
+    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
+    GLubyte textureData[]  = { 0x7f,    0,    0,
+                                  0, 0xff,    0,
+                               0x7f,    0,    0,
+                                  0, 0xff,    0};
+    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+    glTexImage2D( GL_TEXTURE_2D, 0, GL_RGB, 2, 2, 0,
+                  GL_RGB, GL_UNSIGNED_BYTE, textureData );
+
+
+    // BEGIN
+
+#if USE_GLEW
+    glewInit();
+#endif
+
+    glClearColor( 0, 0, 0.5, 1.0 );
+    glClear( GL_COLOR_BUFFER_BIT );
+
+    glColor4f(0.8, 0.8, 0.8, 1);
+
+    glDisable(GL_DEPTH_TEST);
+    glDisable(GL_CULL_FACE);
+    glEnable(GL_TEXTURE_2D);
+    glDisable(GL_BLEND);
+
+    const int kRowSize = 20;
+    GLuint buffer;
+    glGenBuffers(1, &buffer);
+    glBindBuffer(GL_ARRAY_BUFFER, buffer);
+    float fbuf[] = {0, 1, 0, 0, 1,
+                    1, 1, 0, 1, 1,
+                    1, 0, 0, 1, 0,
+                    0, 1, 0, 0, 1,
+                    1, 0, 0, 1, 0,
+                    0, 0, 0, 0, 0};
+    glBufferData(GL_ARRAY_BUFFER, sizeof(fbuf) * sizeof(float), fbuf, GL_STATIC_DRAW);
+
+    glTexCoordPointer(2, GL_FLOAT, kRowSize, (GLvoid*)(3*4));
+    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+
+    glVertexPointer(3, GL_FLOAT, kRowSize, 0);
+    glEnableClientState(GL_VERTEX_ARRAY);
+
+    glDrawArrays(GL_TRIANGLES, 0, 6);
+
+    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
+    glDisableClientState(GL_VERTEX_ARRAY);
+
+    // END
+
+    SDL_GL_SwapBuffers();
+
+    verify();
+
+#if !EMSCRIPTEN
+    SDL_Delay(1500);
+#endif
+
+    SDL_Quit();
+
+    return 0;
+}
diff --git a/tests/runner.py b/tests/runner.py
index c8e3de37..20034f95 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -7654,6 +7654,9 @@ elif 'browser' in str(sys.argv):
       shutil.copyfile(path_from_root('tests', 'screenshot.png'), os.path.join(self.get_dir(), 'screenshot.png'))
       self.btest('gl_ps.c', reference='gl_ps.png', args=['--preload-file', 'screenshot.png'])
 
+    def test_matrix_identity(self):
+      self.btest('gl_matrix_identity.c', expected='-1882984448')
+
     def test_cubegeom_pre(self):
       self.btest('cubegeom_pre.c', expected='-1472804742')