I have original image: http://i.stack.imgur.com/7qYW2.png
How I can to paint over this image, than to get the following: http://i.stack.imgur.com/w3ij3.png
PS: this code not valid:
public void render() {
Gdx.gl.glClearColor(1, 1, 1, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
batcher.begin();
batcher.setColor(Color.BLUE);
batcher.draw(texture, x, y, width, height);
batcher.end();
}
You can use a fragment shader with the following logic:
if(alpha of the pixel is 1.0) then pixel=cyan
else pixel=white
this of course requires the space that surrounds the penguin to be transparent(have a=0)
varying vec4 v_color;
varying vec2 v_texCoords;
uniform sampler2D u_texture;
void main() {
vec4 color=v_color * texture2D(u_texture, v_texCoords);
if(color.a==1.0)gl_FragColor=vec4(0.5,0.5,1,1);
else gl_FragColor=vec(0.0,0.0,0.0,0.0);
}
Full valid code:
String vertexShader = "attribute vec4 a_position;\n" +
"attribute vec4 a_color;\n" +
"attribute vec2 a_texCoord0;\n" +
"\n" +
"uniform mat4 u_projTrans;\n" +
"\n" +
"varying vec4 v_color;\n" +
"varying vec2 v_texCoords;\n" +
"\n" +
"void main() {\n" +
" v_color = a_color;\n" +
" v_texCoords = a_texCoord0;\n" +
" gl_Position = u_projTrans * a_position;\n" +
"}";
String fragmentShader = "#ifdef GL_ES\n" +
"precision mediump float;\n" +
"#endif\n" +
"\n" +
"varying vec4 v_color;\n" +
"varying vec2 v_texCoords;\n" +
"uniform sampler2D u_texture;\n" +
"uniform mat4 u_projTrans;\n" +
"\n" +
"void main() {\n" +
" vec4 color = v_color * texture2D( u_texture, v_texCoords );\n" +
" if( color.a == 0.0 ) gl_FragColor = vec4( color.r, color.g, color.b, 0.0 );\n" +
" else gl_FragColor = vec4( 1.0, 1.0, 1.0, 1.0 );" +
"}";
ShaderProgram shaderProgram = new ShaderProgram(vertexShader,fragmentShader);
public void render() {
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
batch.begin();
batch.setShader(shaderProgram);
batch.draw(texture, x, y, width, height);
batch.end();
}
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.