Are glDrawElements faster?

Are glDrawElements faster?

Unless all of your polys have distinct vertices (pretty unlikely), glDrawElements will be faster than glDrawArray because glDrawElements will take advantage of the fact that repeated vertices will be loaded into the gpu cache, and will not have to be loaded more than once for each poly that that vertex is a part of.

What is the difference between glDrawArrays and glDrawElements?

With glDrawArrays, OpenGL pulls data from the enabled arrays in order, vertex 0, then vertex 1, then vertex 2, and so on. With glDrawElements, you provide a list of vertex numbers. OpenGL will go through the list of vertex numbers, pulling data for the specified vertices from the arrays.

What is Gl_polygon in OpenGL?

GL_POLYGON : Draws a single, convex polygon. Vertices 1 through N define this polygon. For concave polygons you have at least two options: Triangulate the polygon and use GL_TRIANGLES . Use the stencil buffer trick.

What is VAO OpenGL?

A Vertex Array Object (VAO) is an OpenGL Object that stores all of the state needed to supply vertex data (with one minor exception noted below). It stores the format of the vertex data as well as the Buffer Objects (see below) providing the vertex data arrays.

What is GLuint?

GLuint is just a shorter way of typing unsigned int: typedef unsigned int GLenum; typedef unsigned char GLboolean; typedef unsigned int GLbitfield; typedef void GLvoid; typedef signed char GLbyte; /* 1-byte signed */ typedef short GLshort; /* 2-byte signed */ typedef int GLint; /* 4-byte signed */ typedef unsigned char …

What is glBegin and glEnd in OpenGL?

The glBegin and glEnd functions delimit the vertices that define a primitive or a group of like primitives. The glBegin function accepts a single argument that specifies which of ten primitives the vertices compose.

What is glFlush in OpenGL?

glFlush() empties all commands in these buffers and forces all pending commands will to be executed immediately without waiting buffers are full. Therefore glFlush() guarantees that all OpenGL commands made up to that point will complete executions in a finite amount time after calling glFlush().

What is glClearColor in OpenGL?

glClearColor specifies the red, green, blue, and alpha values used by glClear to clear the color buffers. Values specified by glClearColor are clamped to the range [0,1].

What are the advantages of glDrawElements over gldrawarrays?

The advantages of glDrawElements over glDrawArrays are more than just memory saving, which is the naive way of measuring it. There is potentialfor memory saving where vertices can be reused, because an index is typically smaller than a vertex (so even if you have lots of indices on balance they’ll be smaller), but other advantages include:

Are OpenGL Vbos slower than gldrawarrays?

4 OpenGL VBOs are slower than glDrawArrays 2 How can I draw multiple vertexbuffers with indices? 3 Indexed Drawing in OpenGL not working

How many draw calls are in glDrawElements?

1 glDrawElements is 1 draw call. It doesn’t matter (so far as draw call count is concerned) how many vertices or indices you use, 1 glDraw* is 1 draw call.

Can I use gldrawarrays with GL_TRIANGLE_STRIP?

Some mobile GPUs might prefer glDrawArrays with GL_TRIANGLE_STRIP (you would add degenerate triangles to concatenate primitives in this case), and I haven’t even touched on more advanced topics such as primitive restart or multi-draw. Share Improve this answer Follow answered Nov 18 ’16 at 9:45