TESSELATION 1 OUTLINE Tessellation in OpenGL Tessellation of - - PowerPoint PPT Presentation

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Jun 04, 2023 146 likes •348 views

TESSELATION 1 OUTLINE Tessellation in OpenGL Tessellation of Bezier Surfaces Tessellation for Terrain/Height Maps Level of Detail 2 THE PIPELINE Remember the pipeline? OPENGL PIPELINE Tessellation is done in

SLIDE 1

TESSELATION

SLIDE 2

OUTLINE

Tessellation in OpenGL
Tessellation of Bezier Surfaces
Tessellation for Terrain/Height Maps
Level of Detail

SLIDE 3

THE PIPELINE

Remember the pipeline?

SLIDE 4

OPENGL PIPELINE

Tessellation is done in three pipeline stages:
Tessellation Control Shader (TCS)
Allows us to configure the types of triangles generated
Tessellator
Produces a fixed grid of triangles
Tessellation Evaluation Shader (TES)
Allows us to manipulate the grid
TCS and TES are programmable
Middle stage, tessellator, is not programmable

SLIDE 5

THE EXAMPLE

SLIDE 6

TESSELLATION LEVELS

SLIDE 7

VERTEX SHADER

#version 430 uniform mat4 mvp; void main(void) { }

SLIDE 8

TESSELLATION CONTROL SHADER

#version 430 uniform mat4 mvp; layout (vertices = 1) out; void main(void) { gl_TessLevelOuter[0] = 6; gl_TessLevelOuter[2] = 6; gl_TessLevelOuter[1] = 6; gl_TessLevelOuter[3] = 6; gl_TessLevelInner[0] = 12; gl_TessLevelInner[1] = 12; }

SLIDE 9

TESSELLATION EVALUATION SHADER

#version 430 layout (quads, equal_spacing, ccw) in; uniform mat4 mvp; void main (void) { float u = gl_TessCoord.x; float v = gl_TessCoord.y; gl_Position = mvp * vec4(u,0,v,1); }

SLIDE 10

FRAGMENT SHADER

#version 430

ut vec4 color;

uniform mat4 mvp; void main(void) { color = vec4(1.0, 1.0, 0.0, 1.0); }

SLIDE 11

SLIDE 12

TESSELLATION FOR BEZIER SURFACES

SLIDE 13

THE EXAMPLE

SLIDE 14

TESSELLATION FOR TERRAIN / HEIGHT MAPS

SLIDE 15

OVERLY JAGGED

SLIDE 16

HEIGHT MAP AND NORMAL MAP

SLIDE 17

WITH NORMAL MAP AND LIGHTING

SLIDE 18

LEVEL OF DETAIL

SLIDE 19

SUMMARY

Tessellation in OpenGL
Tessellation of Bezier Surfaces
Tessellation for Terrain/Height Maps
Level of Detail