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POProjection and clipping issue?
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copied!<p>I am currently developing a Direct3D 11 rendering engine using C#.</p> <p>I have already succeded in drawing triangles, applying color and textures, etc. The object I am trying to display now is a rotated cube with a side length of 1 placed at the origin of the world space. But I am getting unsatisfying results when applying the view and especially the projection matrix. As it is difficult to explain, I just show you what result I get for different view/projection combinations:</p> <hr> <p>HLSL snippet from my vertex shader:</p> <pre><code>float4x4 wvpMatrix = mul(World, mul(View, Projection)); output.Position = mul(input.Position, wvpMatrix); </code></pre> <p>The world matrix I use:</p> <pre><code>// Static rotation around all three axes matrices.World = Matrix.Identity * Matrix.CreateFromYawPitchRoll(0.5f, 0.6f, 1.0f); </code></pre> <hr> <p><strong>Test A</strong></p> <p>Simple view vector from origin in the positive z direction. No projection used. You can see that the back of the cube is being clipped.</p> <pre><code>matrices.View = Matrix.CreateLookAt(new Vector3(0, 0, 0), new Vector3(0, 0, 1), Vector3.Up); matrices.Projection = Matrix.Identity; </code></pre> <p><img src="https://i.stack.imgur.com/VPdLa.jpg" alt="Cube with back corners clipped"></p> <hr> <p><strong>Test B</strong></p> <p>View matrix stays the same, but now I am using an orthographic projection matrix. This time the front of the cube vanishes. The parts you can see are those which were clipped in Test A.</p> <pre><code>matrices.View = Matrix.CreateLookAt(new Vector3(0, 0, 0), new Vector3(0, 0, 1), Vector3.Up); matrices.Projection = Matrix.CreateOrthographic(2, 2, 0.01f, 100.0f); </code></pre> <p><img src="https://i.stack.imgur.com/BMqpD.jpg" alt="Cube with front corner clipped"></p> <hr> <p><strong>Test C</strong></p> <p>Again no projection, just like in Test A. This time the scene is being viewed from a point three units in the negative z direction. The cube looks distorted when the camera position is not set to the origin of the system. I think there is also some clipping.</p> <pre><code>matrices.View = Matrix.CreateLookAt(new Vector3(0, 0, -3), new Vector3(0, 0, 1), Vector3.Up); matrices.Projection = Matrix.Identity; </code></pre> <p><img src="https://i.stack.imgur.com/FICTy.jpg" alt="Distorted cube"></p> <hr> <p><strong>Test D</strong></p> <p>Finally, I use a perspective projection. Up to now I have not found a camera position from which any part of the cube is visible. All I get is fullscreen cornflower blue.</p> <pre><code>matrices.View = Matrix.CreateLookAt(new Vector3(0, 0, -3), new Vector3(0, 0, 1), Vector3.Up); matrices.Projection = Matrix.CreatePerspectiveFieldOfView(1, 1, 0.1f, 100); </code></pre> <p><img src="https://i.stack.imgur.com/9rWSa.jpg" alt="No visible parts of the cube"></p> <hr> <p>First thing I want to do is drawing the full cube - no clipping. I tried different combinations of near/far plane values but I could not find an acceptable solution. My final goal would be to have a perspective projection. But as you see I can't even get a good orthagonal view of the scene. </p>

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