[osg-users] OSG 3.5.0 (130) GLES2 Shaders Example

[Alex Cham]

Just OSG 3.5.0 (130) GLES2 Shaders Example V2

/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2015 Alex Cham
 *
 * This example is open source and may be redistributed and/or modified under
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 *
 * This example is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * OpenSceneGraph Public License for more details.

#define OPENSCENEGRAPH_MAJOR_VERSION    3
#define OPENSCENEGRAPH_MINOR_VERSION    5
#define OPENSCENEGRAPH_PATCH_VERSION    0
#define OPENSCENEGRAPH_SOVERSION        130

$ git log -1
commit bc3a77cb1561ed2e47e88ab507180bcf15309f31
Author: Robert OSFIELD <robert.osfield at gmail.com>
Date:   Fri Jul 17 18:31:22 2015 +0000
*/
#include <osgViewer/Viewer>

#include <osg/ShapeDrawable>
#include <osg/Geode>
#include <osg/Vec3>

#include <osg/Program>
#include <osg/Shader>
#include <osg/Uniform>

using namespace osg;


static const char *vertexShaderSource = {
		"#version 100\n"
//		"uniform mat4 mvp_matrix;// model-view-projection matrix\n"
		"uniform mat3 normal_matrix;// normal matrix\n"
		"uniform vec3 ec_light_dir;// light direction in eye coords\n"
		"attribute vec4 a_vertex;// vertex position\n"
		"attribute vec3 a_normal;// vertex normal\n"
//		"attribute vec2 a_texcoord;// texture coordinates\n"
//		"varying float v_diffuse;\n"
//		"varying vec2 v_texcoord;\n"
		"void main(void)\n"
		"{\n"
		"// put vertex normal into eye coords\n"
		"vec3 ec_normal = normalize(normal_matrix * a_normal);\n"
//		"// emit diffuse scale factor, texcoord, and position\n"
//		"v_diffuse = max(dot(ec_light_dir, ec_normal), 0.0);\n"
//		"v_texcoord= a_texcoord;\n"
		"gl_Position = gl_ModelViewProjectionMatrix * a_vertex;\n"
		"}\n"};

static const char *fragmentShaderSource = {
		"#version 100\n"
		"precision mediump float;\n"
		"void main()\n"
		"{\n"
		"gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);\n"
		"}\n"};


int main(int, char **)
{
	osg::setNotifyLevel(osg::INFO);


    // construct the viewer.
    osgViewer::Viewer viewer;

    // use a geode with a Box ShapeDrawable
    osg::Geode* geode = new osg::Geode();
    geode->addDrawable(new osg::ShapeDrawable(new osg::Box(osg::Vec3(0.0f,0.0f,0.0f),1.0f)));

    osg::StateSet *ss = geode->getOrCreateStateSet();
    osg::Program* program = new osg::Program;

	program->addShader( new osg::Shader( osg::Shader::VERTEX, vertexShaderSource ) );
	program->addShader( new osg::Shader( osg::Shader::FRAGMENT, fragmentShaderSource ) );
	ss->setAttributeAndModes(program, osg::StateAttribute::ON);

    viewer.setSceneData(geode);
    return viewer.run();
}
/*

mkdir ./GLES2ContextBuild
cd ./GLES2ContextBuild

cmake \
-DCMAKE_C_COMPILER="/usr/bin/clang" \
-DCMAKE_CXX_COMPILER="/usr/bin/clang++" \
-DCMAKE_CXX_FLAGS="-std=c++11 -v -Wall" \
-DBUILD_OSG_EXAMPLES=1 \
-DOSG_GL1_AVAILABLE=OFF \
-DOSG_GL2_AVAILABLE=OFF \
-DOSG_GL3_AVAILABLE=OFF \
-DOSG_GLES1_AVAILABLE=OFF \
-DOSG_GLES2_AVAILABLE=ON \
-DOPENGL_INCLUDE_DIR=/usr/include/ \
-DOPENGL_LIBRARY=/usr/lib/x86_64-linux-gnu/libGLESv2.so \
-DOPENGL_egl_LIBRARY=/usr/lib/x86_64-linux-gnu/libEGL.so \
-DOSG_GL_DISPLAYLISTS_AVAILABLE=OFF \
-DSG_GL_MATRICES_AVAILABLE=OFF \
-DOSG_GL_VERTEX_FUNCS_AVAILABLE=OFF \
-DOSG_GL_VERTEX_ARRAY_FUNCS_AVAILABLE=OFF \
-DOSG_GL_FIXED_FUNCTION_AVAILABLE=OFF \
-DOSG_CPP_EXCEPTIONS_AVAILABLE=OFF \
../GLES2ContextSource

http://trac.openscenegraph.org/projects/osg/wiki/Community/OpenGL-ES



Based on OSG osgsimpleshaders.cpp
http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk/examples/osgsimpleshaders/osgsimpleshaders.cpp

See Also Hello Triangle: An OpenGL ES 2.0 Example
https://www.khronos.org/assets/uploads/books/openglr_es_20_programming_guide_sample.pdf

OpenGL ES 2.0 API & OpenGL ES Shading Language 1.0 Quick Reference Card
https://www.khronos.org/files/opengles20-reference-card.pdf

OpenGL ES Shading Language Version 1.00
https://www.khronos.org/files/opengles_shading_language.pdf
 */


Thank you!

Cheers,
Alex

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Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=64385#64385