StackOverflow2013

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POIssue with glPolygonMode - GL_FILL "skipping" vertices
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copied!<p>I'm having a weird issue when trying to draw a polygon and filling it with a particular color:</p> <p>If I set the polygon mode as:</p> <p><code>glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);</code></p> <p>The polygon renders just fine:</p> <p><img src="https://i.stack.imgur.com/mPeC4.png" alt="Polygon rendered after setting the polygon fill mode to GL_LINE"></p> <p>However, as soon as I replace that line with the following:</p> <p><code>glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);</code></p> <p>The polygon doesn't fill right, but it seems like most lines get projected towards its first vertex, or something along those lines:</p> <p><img src="https://i.stack.imgur.com/BosyO.png" alt="enter image description here"></p> <p>I'm obviously doing something wrong. What I want to do is keep the color inside the polygon, however it seems to be ignoring several vertices. What might be wrong?</p> <p>Here's some selected parts of my code that might be of interest. I'm skipping over some data structures loading and other stuff that might not be very relevant:</p> <pre><code>int main(int argc, char **argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE); glutInitWindowSize(640, 480); glutInitWindowPosition(150, 100); glutCreateWindow("CR-View GL"); glutDisplayFunc(display); glutMainLoop(); return 0; } void display(void) { glClearColor(0, 0, 0, 0); glClear(GL_COLOR_BUFFER_BIT); /* Set drawing color */ glColor3f(1, 0, 1); drawPolys(currentDrawingMode); /* Clear screen and draw */ glutSwapBuffers(); } // Draws the polygons void drawPolys (int id) { int poly, vertex; // set wireframe mode (if an empty polygon is required) if (id == 0) { glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); } //Sets color fill mode if (id == 1) { glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); } // Draw each polygon... for (poly = 0; poly < polyCount; poly++) { glBegin(GL_POLYGON); // Draw each vertex... for (vertex = 0; vertex < Polygons[poly].vertexCount; vertex++) { glVertex2f((float)Polygons[poly].vertices[vertex].x, (float)Polygons[poly].vertices[vertex].y); } glEnd(); } } </code></pre>

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