After spending some reputation on a unsuccessful bounty to get some help on this issue, I finally realized how complex was the problem I was interested in. The few individuals that have accomplished this task don’t share much. During my research I found different ways to achieve what I was looking for. One of the … Read more
The model, view and projection matrices are three separate matrices. Model maps from an object’s local coordinate space into world space, view from world space to camera space, projection from camera to screen. If you compose all three, you can use the one result to map all the way from object space to screen space, … Read more
Mind that these commands exist since the early days of OpenGL. glFlush ensures that previous OpenGL commands must complete in finite time (OpenGL 2.1 specs, page 245). If you draw directly to the front buffer, this shall ensure that the OpenGL drivers starts drawing without too much delay. You could think of a complex scene … Read more
OpenTK is an improvement over the Tao API, as it uses idiomatic C# style with overloading, strongly-typed enums, exceptions, and standard .NET types: GL.Begin(BeginMode.Points); GL.Color3(Color.Yellow); GL.Vertex3(Vector3.Up); as opposed to Tao which merely mirrors the C API: Gl.glBegin(Gl.GL_POINTS); // double “gl” prefix Gl.glColor3ub(255, 255, 0); // have to pass RGB values as separate args Gl.glVertex3f(0, 1, … Read more
“Vertex Array Object” is brought to you by the OpenGL ARB Subcommittee for Silly Names. Think of it as a geometry object. (As an old time SGI Performer programmer, I call them geosets.) The instance variables/members of the object are your vertex pointer, normal pointer, color pointer, attrib N pointer, … When a VAO is … Read more
The identity matrix, in terms of the projection and modelview matrices, essentially resets the matrix back to its default state. As you hopefully know, glTranslate and glRotate are always relative to the matrix’s current state. So for instance, if you call glTranslate, you are translating from the matrix’s current ‘position’, not from the origin. But … Read more
All About OpenGL Objects The standard model for OpenGL objects is as follows. Objects have state. Think of them as a struct. So you might have an object defined like this: struct Object { int count; float opacity; char *name; }; The object has certain values stored in it and it has state. OpenGL objects … Read more
A fragment shader is the same as pixel shader. One main difference is that a vertex shader can manipulate the attributes of vertices. which are the corner points of your polygons. The fragment shader on the other hand takes care of how the pixels between the vertices look. They are interpolated between the defined vertices … Read more
There’s no official extension in the spec. OpenGL doesn’t handle loading shaders from files; you just pass in the shader code as a string, so there’s no specific file format. However, glslang, Khronos’ reference GLSL compiler/validator, uses the following extensions to determine what type of shader that the file is for: .vert – a vertex … Read more
The Framebuffer object is not actually a buffer, but an aggregator object that contains one or more attachments, which by their turn, are the actual buffers. You can understand the Framebuffer as C structure where every member is a pointer to a buffer. Without any attachment, a Framebuffer object has very low footprint. Now each … Read more