TextManager.java

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//package ri.blog.opengl008;
package com.introlab.rtabmap;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;
import java.util.Iterator;
import java.util.Vector;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.opengl.GLES20;
import android.opengl.GLUtils;
import android.text.TextPaint;

public class TextManager {
        
        /* SHADER Text
         * 
         * This shader is for rendering 2D text textures straight from a texture
         * Color and alpha blended.
         * 
         */
        public static final String vs_Text =
                "uniform mat4 uMVPMatrix;" +
                "attribute vec4 vPosition;" +
                "attribute vec2 a_texCoord;" +
                "varying vec2 v_texCoord;" +
            "void main() {" +
            "  gl_Position = uMVPMatrix * vPosition;" +
            "  v_texCoord = a_texCoord;" +
            "}";
        public static final String fs_Text =
            "precision mediump float;" +
            "uniform float uColor;" +
            "varying vec2 v_texCoord;" +
        "uniform sampler2D s_texture;" +
            "void main() {" +
            "  gl_FragColor = texture2D( s_texture, v_texCoord );" +
            "  gl_FragColor.rgb *= uColor;" +
            "}";
        
        public static int sp_Text;
        
        public static final int RI_TEXT_TEXTURE_SIZE = 512; // 512
        public static final float RI_TEXT_HEIGHT_BASE = 32.0f;
        public static final char RI_TEXT_START = ' ';
        public static final char RI_TEXT_STOP = '~'+1;
        
        public float getMaxTextHeight() {return mTextHeight;}
        
        private float mUVWidth;
        private float mUVHeight;
        private float mTextHeight;
        private float mColor;
        
        private FloatBuffer vertexBuffer;
        private FloatBuffer textureBuffer;
        private ShortBuffer drawListBuffer;
        
        private float[] vecs;
        private float[] uvs;
        private short[] indices;
        
        private int index_vecs;
        private int index_indices;
        private int index_uvs;

        private int texturenr;
        private int[] mTextures;
        
        private float uniformscale = 1.0f;
        
        float[] mCharacterWidth;
        
        public TextManager(Context context)
        {
                // Create the arrays
                vecs = new float[3 * 10];
                uvs = new float[2 * 10];
                indices = new short[10];
                
                // init as 0 as default
                texturenr = 0;
                
                // Text shader
                int vshadert = TextManager.loadShader(GLES20.GL_VERTEX_SHADER, TextManager.vs_Text);
                int fshadert = TextManager.loadShader(GLES20.GL_FRAGMENT_SHADER, TextManager.fs_Text);

                TextManager.sp_Text = GLES20.glCreateProgram();
                GLES20.glAttachShader(TextManager.sp_Text, vshadert);
                GLES20.glAttachShader(TextManager.sp_Text, fshadert);           // add the fragment shader to program
                GLES20.glLinkProgram(TextManager.sp_Text);                  // creates OpenGL ES program executables
                
                // Generate Textures, if more needed, alter these numbers.
                mTextures = new int[1];
                GLES20.glGenTextures(1, mTextures, 0);
                
                // Create an empty, mutable bitmap
                Bitmap bitmap = Bitmap.createBitmap(RI_TEXT_TEXTURE_SIZE, RI_TEXT_TEXTURE_SIZE, Bitmap.Config.ARGB_4444);
                // get a canvas to paint over the bitmap
                Canvas canvas = new Canvas(bitmap);
                bitmap.eraseColor(0);

                // Draw the text
                TextPaint textPaint = new TextPaint();
                textPaint.setTextSize(RI_TEXT_HEIGHT_BASE);
                textPaint.setColor(Color.WHITE);
                textPaint.setAntiAlias(true);
                textPaint.setTypeface(Typeface.create("Arial", Typeface.BOLD));
                
                // compute real maximum height
                mTextHeight=0.0f;
                for(char c=RI_TEXT_START; c<RI_TEXT_STOP; ++c)
                {
                        Rect textBounds = new Rect();
                        textPaint.getTextBounds(String.valueOf(c), 0, 1, textBounds);
                        if(textBounds.height() + textBounds.bottom > mTextHeight)
                        {
                                mTextHeight = textBounds.height() + textBounds.bottom;
                        }
                }
                mUVWidth = (float)RI_TEXT_HEIGHT_BASE/(float)RI_TEXT_TEXTURE_SIZE;
                mUVHeight = mTextHeight/(float)RI_TEXT_TEXTURE_SIZE;
                mColor = 1.0f;
                
                int colCount = RI_TEXT_TEXTURE_SIZE/(int)RI_TEXT_HEIGHT_BASE;
                mCharacterWidth = new float[RI_TEXT_STOP-RI_TEXT_START];
                int i=0;
                for(char c=RI_TEXT_START; c<RI_TEXT_STOP; ++c)
                {
                        Rect textBounds = new Rect();
                        textPaint.getTextBounds(String.valueOf(c), 0, 1, textBounds);
                        canvas.drawText(String.valueOf(c), (i%colCount)*RI_TEXT_HEIGHT_BASE, (i/colCount) * mTextHeight + RI_TEXT_HEIGHT_BASE, textPaint);
                        mCharacterWidth[i] = textPaint.measureText(String.valueOf(c));
                        ++i;
                }
                
                GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mTextures[0]);
                GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR);
        GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0);
                
                //Clean up
                bitmap.recycle();
        }
        
        public void setTextureID(int val)
        {
                texturenr = val;
        }
        
        public static int loadShader(int type, String shaderCode){

            // create a vertex shader type (GLES20.GL_VERTEX_SHADER)
            // or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)
            int shader = GLES20.glCreateShader(type);

            // add the source code to the shader and compile it
            GLES20.glShaderSource(shader, shaderCode);
            GLES20.glCompileShader(shader);
            
            // return the shader
            return shader;
        }
        
        
        public void AddCharRenderInformation(float[] vec, float[] cs, float[] uv, short[] indi)
        {
                // We need a base value because the object has indices related to 
                // that object and not to this collection so basicly we need to 
                // translate the indices to align with the vertexlocation in ou
                // vecs array of vectors.
                short base = (short) (index_vecs / 3);
                        
                // We should add the vec, translating the indices to our saved vector
                for(int i=0;i<vec.length;i++)
                {
                        vecs[index_vecs] = vec[i];
                        index_vecs++;
                }
                
                // We should add the uvs
                for(int i=0;i<uv.length;i++)
                {
                        uvs[index_uvs] = uv[i];
                        index_uvs++;
                }

                // We handle the indices
                for(int j=0;j<indi.length;j++)
                {
                        indices[index_indices] = (short) (base + indi[j]);
                        index_indices++;
                }
        }

        public void PrepareDrawInfo(Vector<TextObject> txtcollection)
        {
                // Reset the indices.
                index_vecs = 0;
                index_indices = 0;
                index_uvs = 0;
                
                // Get the total amount of characters
                int charcount = 0;
                for (TextObject txt : txtcollection) {
                        if(txt!=null)
                        {
                                if(!(txt.text==null))
                                {
                                        charcount += txt.text.length(); 
                                }
                        }
                }
                
                // Create the arrays we need with the correct size.
                vecs = null;
                uvs = null;
                indices = null;
                
                vecs = new float[charcount * 12];
                uvs = new float[charcount * 8];
                indices = new short[charcount * 6];

        }
        
        public void PrepareDraw(Vector<TextObject> txtcollection)
        {
                // Setup all the arrays
                PrepareDrawInfo(txtcollection);
                
                // Using the iterator protects for problems with concurrency
                for( Iterator< TextObject > it = txtcollection.iterator(); it.hasNext() ; )
            {
                TextObject txt = it.next();
                if(txt!=null)
                        {
                        if(!(txt.text==null))
                                {
                                        convertTextToTriangleInfo(txt);
                                }
                        }
            }
        }
        
        public void Draw(float[] m)
        {
                if(vecs.length > 0)
                {
                        GLES20.glDisable(GLES20.GL_DEPTH_TEST);
                        GLES20.glEnable(GLES20.GL_BLEND);
                        
                        // Set the correct shader for our grid object.
                        GLES20.glUseProgram(sp_Text);
                        
                        // The vertex buffer.
                        ByteBuffer bb = ByteBuffer.allocateDirect(vecs.length * 4);
                        bb.order(ByteOrder.nativeOrder());
                        vertexBuffer = bb.asFloatBuffer();
                        vertexBuffer.put(vecs);
                        vertexBuffer.position(0);
                        
                        // The texture buffer
                        ByteBuffer bb2 = ByteBuffer.allocateDirect(uvs.length * 4);
                        bb2.order(ByteOrder.nativeOrder());
                        textureBuffer = bb2.asFloatBuffer();
                        textureBuffer.put(uvs);
                        textureBuffer.position(0);
                        
                        // initialize byte buffer for the draw list
                        ByteBuffer dlb = ByteBuffer.allocateDirect(indices.length * 2);
                        dlb.order(ByteOrder.nativeOrder());
                        drawListBuffer = dlb.asShortBuffer();
                        drawListBuffer.put(indices);
                        drawListBuffer.position(0);
                        
                        // get handle to vertex shader's vPosition member
                    int mPositionHandle = GLES20.glGetAttribLocation(sp_Text, "vPosition");
                    
                    // Enable a handle to the triangle vertices
                    GLES20.glEnableVertexAttribArray(mPositionHandle);
                 
                    // Prepare the background coordinate data
                    GLES20.glVertexAttribPointer(mPositionHandle, 3,
                                                 GLES20.GL_FLOAT, false,
                                                 0, vertexBuffer);
                    
                    int mTexCoordLoc = GLES20.glGetAttribLocation(sp_Text, "a_texCoord" );
                    
                    // Prepare the texturecoordinates
                    GLES20.glVertexAttribPointer ( mTexCoordLoc, 2, GLES20.GL_FLOAT,
                        false, 
                        0, textureBuffer);
        
                    GLES20.glEnableVertexAttribArray ( mPositionHandle );
                GLES20.glEnableVertexAttribArray ( mTexCoordLoc );
        
                    // get handle to shape's transformation matrix
                int mtrxhandle = GLES20.glGetUniformLocation(sp_Text, "uMVPMatrix");
                
                // Apply the projection and view transformation
                GLES20.glUniformMatrix4fv(mtrxhandle, 1, false, m, 0);
                
                // get handle to color value
                int colorhandle = GLES20.glGetUniformLocation(sp_Text, "uColor");
                GLES20.glUniform1f(colorhandle, mColor);
                
                int mSamplerLoc = GLES20.glGetUniformLocation (sp_Text, "s_texture" );
                
                // Texture activate unit 0
                GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
                        // Bind the texture to this unit.
                GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mTextures[0]);
                // Set the sampler texture unit to our selected id
                    GLES20.glUniform1i ( mSamplerLoc, texturenr);
                    
                // Draw the triangle
                GLES20.glDrawElements(GLES20.GL_TRIANGLES, indices.length, GLES20.GL_UNSIGNED_SHORT, drawListBuffer);
        
                // Disable vertex array
                GLES20.glDisableVertexAttribArray(mPositionHandle);
                GLES20.glDisableVertexAttribArray(mTexCoordLoc);
                }
        }
        
        private void convertTextToTriangleInfo(TextObject val)
        {               
                // Get attributes from text object
                float x = val.x;
                float y = val.y;
                String text = val.text;
                
                // Create 
                for(int j=0; j<text.length(); j++)
                {
                        // get ascii value
                        char c = text.charAt(j);
                        int c_val = (int)c;
                        
                        int indx = c_val-RI_TEXT_START;
                        
                        if(indx<0 || indx>=mCharacterWidth.length) {
                                // unknown character, we will add a space for it to be save.
                                indx = 0;
                        }
                        
                        int colCount = RI_TEXT_TEXTURE_SIZE/(int)RI_TEXT_HEIGHT_BASE;
                        
                        // Calculate the uv parts
                        int row = indx / colCount;
                        int col = indx % colCount;
                        
                        float v = row * mUVHeight;
                        float v2 = v + mUVHeight;
                        float u = col * mUVWidth;
                        float u2 = u + mCharacterWidth[indx]/(float)RI_TEXT_TEXTURE_SIZE;
                        
                        // Creating the triangle information
                        float[] vec = new float[12];
                        float[] uv = new float[8];
                        float[] colors = new float[16];
                        
                        vec[0] = x;
                        vec[1] = y + (mTextHeight * uniformscale);
                        vec[2] = 0.99f;
                        vec[3] = x;
                        vec[4] = y;
                        vec[5] = 0.99f;
                        vec[6] = x + (mCharacterWidth[indx] * uniformscale);
                        vec[7] = y;
                        vec[8] = 0.99f;
                        vec[9] = x + (mCharacterWidth[indx] * uniformscale);
                        vec[10] = y + (mTextHeight * uniformscale);
                        vec[11] = 0.99f;
                
                        colors = new float[]
                                        {val.color[0], val.color[1], val.color[2], val.color[3],
                                                val.color[0], val.color[1], val.color[2], val.color[3],
                                                val.color[0], val.color[1], val.color[2], val.color[3],
                                                val.color[0], val.color[1], val.color[2], val.color[3]
                                                                                   };
                        // 0.001f = texture bleeding hack/fix
                        uv[0] = u+0.001f;
                        uv[1] = v+0.001f;
                        uv[2] = u+0.001f;
                        uv[3] = v2-0.001f;
                        uv[4] = u2-0.001f;
                        uv[5] = v2-0.001f;
                        uv[6] = u2-0.001f;
                        uv[7] = v+0.001f;
                        
                        short[] inds = {0, 1, 2, 0, 2, 3};
                        
                        // Add our triangle information to our collection for 1 render call.
                        AddCharRenderInformation(vec, colors, uv, inds);
                        
                        // Calculate the new position
                        x += (mCharacterWidth[indx]  * uniformscale);
                }
        }

        public float getUniformscale() {
                return uniformscale;
        }

        public void setUniformscale(float uniformscale) {
                this.uniformscale = uniformscale;
        }
        
        public void setColor(float color) {
                mColor = color;
        }
}