Instal the new for apple FreeTube 0.19.112/10/2023 ![]() ![]() We used an array to retrieve the normals in the GS. In order to tell OpenGL we output two triangles, we must modify a bit the output layout compared to our first GS in the part 1: If you try to translate along the normal in another space (world, view, projection), you will end up with strange results… The translation is done in object space (object space? refresh your memory with this article about transformation spaces) that’s why we do all the computations in the geometry shader. This second triangle is translated along the vertex normal. The geometry doubler shader outputs two triangles: one the is input triangle and the second one is a new triangle: the double. The number of elements of the array is automatically set by the GLSL compiler according to the input layout (here a triangle). There is one normal per vertex and the size of the array is… 3 elements because the GS takes a triangle as input data. Remember, we are in a geometry shader: that’s why we retrieve per-vertex normals in an array. Gl_Position = viewProjectionMatrix * world_pos Vec4 world_pos = modelMatrix * (gl_in.gl_Position + normalize(N) * 10.0) = Second triangle - translated version of the Gl_Position = projectionMatrix * view_pos Vec4 view_pos = modelViewMatrix * gl_in.gl_Position = First triangle - identical to the input one. Mat4 viewProjectionMatrix = projectionMatrix * viewMatrix Mat4 modelViewMatrix = viewMatrix * modelMatrix Layout(triangle_strip, max_vertices=6) out Now let’s see how to read the vertex normal in the GS. In this vertex shader, normal is a vertex attribute and is sent to the geometry shader like the built-in gl_Position. Why? because the vertex transformation will be done in the geometry shader. ![]() ![]() The geometry doubler allows us to see how to pass data from vertex shader to geometry shader.Īs you can see, this vertex shader is rather mininal (a pass-trought VS). Like in the first example, the GLSL program includes a VS, A GS and a PS. The GS doubler demo in GeeXLab – green: input geometry – yellow: duplicated geometry This geometry doubler duplicates the input primitives and translates them along the vertex normal. Let’s see a more interesting use of the GS: a geometry doubler. You missed the first part of this introduction to GS? No problem, you can find it HERE.ġ – Doubling the geometry with the geometry shader 1 – Doubling the geometry with the geometry shader. ![]()
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |