1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # Licensed under the Apache License, Version 2.0 (the "License");
4 # you may not use this file except in compliance with the License.
5 # You may obtain a copy of the License at
7 # http://www.apache.org/licenses/LICENSE-2.0
9 # Unless required by applicable law or agreed to in writing, software
10 # distributed under the License is distributed on an "AS IS" BASIS,
11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 # See the License for the specific language governing permissions and
13 # limitations under the License.
15 # Example of using `GamnitDisplay` to setup a screen for custom calls to OpenGL ES 2.0
17 # This example does not support the lifecycle of mobile platforms, as such it only works on desktop computers.
20 # * The book OpenGL ES 2.0 Programming Guide
21 # * https://code.google.com/p/opengles-book-samples/source/browse/trunk/LinuxX11/Chapter_2/Hello_Triangle/Hello_Triangle.c
22 module standalone_triangle
is example
25 import gamnit
::display
27 if "NIT_TESTING".environ
== "true" then exit
(0)
30 var display
= new GamnitDisplay
33 var width
= display
.width
34 var height
= display
.height
35 print
"Width: {width}"
36 print
"Height: {height}"
38 # Custom calls to OpenGL ES 2.0
39 assert glGetError
== gl_NO_ERROR
40 assert gl
.shader_compiler
else print
"Cannot compile shaders"
44 var program
= new GLProgram
45 if not glIsProgram
(program
) then
46 print
"Program is not ok: {glGetError.to_s}\nLog:"
47 print glGetProgramInfoLog
(program
)
50 assert glGetError
== gl_NO_ERROR
53 var vertex_shader
= new GLVertexShader
54 assert glIsShader
(vertex_shader
) else print
"Vertex shader is not ok: {glGetError}"
55 glShaderSource
(vertex_shader
, """
56 attribute vec4 vPosition;
59 gl_Position = vPosition;
61 """@glsl_vertex_shader
.to_cstring
)
62 glCompileShader vertex_shader
63 assert vertex_shader
.is_compiled
else print
"Vertex shader compilation failed with: {glGetShaderInfoLog(vertex_shader)} {glGetProgramInfoLog(program)}"
64 assert glGetError
== gl_NO_ERROR
67 var fragment_shader
= new GLFragmentShader
68 assert glIsShader
(fragment_shader
) else print
"Fragment shader is not ok: {glGetError}"
69 glShaderSource
(fragment_shader
, """
70 precision mediump float;
73 gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
75 """@glsl_fragment_shader
.to_cstring
)
76 glCompileShader fragment_shader
77 assert fragment_shader
.is_compiled
else print
"Fragment shader compilation failed with: {glGetShaderInfoLog(fragment_shader)}"
78 assert glGetError
== gl_NO_ERROR
81 glAttachShader
(program
, vertex_shader
)
82 glAttachShader
(program
, fragment_shader
)
83 program
.bind_attrib_location
(0, "vPosition")
85 assert program
.is_linked
else print
"Linking failed: {glGetProgramInfoLog(program)}"
86 assert glGetError
== gl_NO_ERROR
89 var vertices
= [0.0, 0.5, 0.0, -0.5, -0.5, 0.0, 0.5, -0.5, 0.0]
90 var vertex_array
= new VertexArray(0, 3, vertices
)
91 vertex_array
.attrib_pointer
92 glClearColor
(0.5, 0.0, 0.5, 1.0)
95 assert glGetError
== gl_NO_ERROR
96 glViewport
(0, 0, width
, height
)
97 glClear gl_COLOR_BUFFER_BIT
101 glDrawArrays
(gl_TRIANGLES
, 0, 3)
107 glDeleteProgram program
108 glDeleteShader vertex_shader
109 glDeleteShader fragment_shader