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![Define Attribute Values
void glVertexAttrib{1234}f(GLuint index,
GLfloat value[N]);!
void glVertexAttrib{1234}fv(GLuint index,
const GLfloat *values);
26](https://image.slidesharecdn.com/opengl-141015094010-conversion-gate02/75/OpenGL-Introduction-26-2048.jpg)
![Define Uniform Values
void glUniform{1234}{if}(GLint index, T
value[N]);!
void glUniform{1234}{if}v(GLint index,
GLsizei count, const T *value);!
void glUniformMatrix{234}fv(GLint index,
GLsizei count, GLboolean transpose, const
GLfloat *value);
29](https://image.slidesharecdn.com/opengl-141015094010-conversion-gate02/75/OpenGL-Introduction-29-2048.jpg)
Uploaded byYi-Lung Tsai
OpenGL Introduction
This document provides an introduction to OpenGL concepts including state machines, primitives, buffers, shaders, attributes and uniforms, and drawing. It explains key OpenGL functions and terms like rendering settings, buffer objects, vertex and fragment shaders, and clearing and drawing. Examples of rendering a simple 3D scene with vertices, colors, and textures are provided.
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OpenGL Introduction
- 1.
- 2. State machine! Primitives! Buffers! Shaders! Attributes and uniforms! Drawing
- 4. Port Crane Cratesinside each container are our instances! Containers are OpenGL’s objects ! textures, shaders, meshes! Port crane is OpenGL API 4 State Machine
- 5. Primitives GL_POINTS! GL_LINES! GL_LINE_STRIP! GL_LINE_LOOP! GL_TRIANGLES! GL_TRIANGLE_STRIP! GL_TRIANGLE_FAN 5
- 8. Rendering Settings voidglPolygonMode(GLenum face, GLenum mode);! GL_FRONT_AND_BACK GL_POINT ! void glFrontFace(GLenum mode);! ! void glCullFace(GLenum mode); GL_LINE GL_FILL GL_CW GL_CCW GL_FRONT GL_BACK GL_FRONT_AND_BACK 8
- 9. Buffers Temporary optimizedstorage! Render buffers! Frame buffers! Buffer objects 9
- 10. Render Buffer Color! Store final colored (RGB) image! Depth! Store final Z depth information! Stencil! Store visible part of object 10
- 11. Frame Buffer Storefinal image! Combination of render buffers 11
- 12. Buffer Object Holdinformations about 3D objects! Structures! Indices 12
- 13. Structures vs. Indices {v1, v2, v3}, {v1, v3, v4}, …! ! {v1, v2, v3, v4, …} (0, 1, 2, 0, 2, 3, …) 13
- 14. One Buffer ata Time OpenGL GL_ARRAY_BUFFER GL_ELEMENT_ARRAY_BUFFER GL_TEXTURE_BUFFER Buffer1 Buffer2 Buffer3 Buffer4
- 15. Create Buffer voidglGenBuffers(GLsizei n, GLuint *buffers);! ! void glBindBuffers(GLenum target, GLuint buffer); GL_ARRAY_BUFFER GL_ELEMENT_ARRAY_BUFFER 15
- 16. Set Buffer Data void glBufferData(GLenum target, GLsizeiptr size, const GLvoid *data, GLenum usage);! ! _STATIC_ _DYNAMIC_ _STREAM_ _DRAW _READ _COPY GL_STATIC_DRAW ! void glBufferSubData(GLenum target, GLintptr offset, GLsizeiptr size, const GLvoid *data); 16
- 17. Copy Buffer Data void glCopyBufferSubData(GLenum readtarget, GLenum writetarget, GLintptr readoffset, GLintptr writeoffset, GLsizeiptr size); 17
- 18. Get Buffer Data void glGetBufferSubData(GLenum target, GLintptr offset, GLsizeiptr size, GLvoid *data); 18
- 19. Access Content Buffer void* glMapBuffer(GLenum target, GLenum access);! GL_READ_ONLY GL_WRITE_ONLY GL_READ_WRITE ! GLboolean glUnmapBuffer(GLenum target) 19
- 21. Create Shader GLuintglCreateShader(GLenum type);! ! void glShaderSource(GLuint shader, GLsizei count, const GLchar **string, const GLint *length);! void glCompileShader(GLuint shader); 21 GL_VERTEX_SHADER GL_FRAGMENT_SHADER
- 22. Create Program GLuintglCreateProgram(void);! void glAttachShader(GLuint program, GLuint shader);! void glLinkProgram(GLuint program);! void glUseProgram(GLuint program); 22
- 23.
- 24. Attribute Location 1.Defined fixed location in shader! 2. Bind attribute location before linking shader code! void glBindAttribLocation(GLuint program, GLuint index, const GLchar *name);! 3. Get attribute location after linking shader code! GLint glGetAttribLocation(GLuint program, const GLchar *name); 24
- 25. Uniform Location Getuniform location after linking shader code! GLint glGetUniformLocation(GLuint program, const GLchar *name); 25
- 26. Define Attribute Values void glVertexAttrib{1234}f(GLuint index, GLfloat value[N]);! void glVertexAttrib{1234}fv(GLuint index, const GLfloat *values); 26
- 27. Attribute Pointer voidglVertexAttribPointer(GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, const GLvoid *ptr);! ! Required while using glVertexAttribPointer void glGenVertexArrays(GLsizei n, GLuint *arrays);! void glBindVertexArrays(GLuint array); 27
- 28. Using Attribute Pointer void glEnableVertexAttribArray(GLuint index);! void glDisableVertexAttribArray(GLuint index); 28
- 29. Define Uniform Values void glUniform{1234}{if}(GLint index, T value[N]);! void glUniform{1234}{if}v(GLint index, GLsizei count, const T *value);! void glUniformMatrix{234}fv(GLint index, GLsizei count, GLboolean transpose, const GLfloat *value); 29
- 30. Clear void glClearColor(GLfloztred, GLfloat green, GLfloat blue, GLfloat alpha);! void glClear(GLbitfield mask); 30 GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT GL_STENCIL_BUFFER_BIT
- 31. Drawing void glDrawArrays(GLenummode, GLint first, GLsizei count);! ! ! void glDrawElements(GLenum mode, GLsizei count, GLenum type, const GLvoid *indices); 31 GL_POINTS GL_LINES GL_LINE_STRIP GL_LINE_LOOP GL_TRIANGLES GL_TRIANGLE_STRIP GL_TRIANGLE_FAN GL_UNSIGNED_BYTE GL_UNSIGNED_SHORT GL_UNSIGNED_INT
- 32. Restarting Index voidglPrimitiveRestartIndex(GLuint index); 32
- 33. Sample v0! p(-1,-1,0,1)! c(1,1,1,1) v1! p(1,-1,0,1)! c(1,1,0,1) v2! p(-1,1,0,1)! c(1,0,1,1) v3! p(1,1,0,1)! c(0,1,1,1)
- 34. References http://blog.db-in.com/all-about-opengl-es-2-x-part-1/! http://www.dreamstime.com/stock-images-port-cranes-image25107404 ! http://blog.db-in.com/all-about-opengl-es-2-x-part-2/! OpenGL Programming Guide