From d376d07c1250f257f975c87d91a768f689dd1249 Mon Sep 17 00:00:00 2001
From: Hannes Janetzek <hannes.janetzek@gmail.com>
Date: Mon, 28 Jan 2013 00:44:07 +0100
Subject: [PATCH] use short vertices, add docs
---
.../renderer/overlays/TestLineOverlay.java | 97 +++++++++++++------
1 file changed, 68 insertions(+), 29 deletions(-)
diff --git a/src/org/oscim/renderer/overlays/TestLineOverlay.java b/src/org/oscim/renderer/overlays/TestLineOverlay.java
index a61e8f5e..1910afbb 100644
--- a/src/org/oscim/renderer/overlays/TestLineOverlay.java
+++ b/src/org/oscim/renderer/overlays/TestLineOverlay.java
@@ -16,7 +16,6 @@ package org.oscim.renderer.overlays;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
-import java.nio.FloatBuffer;
import java.nio.ShortBuffer;
import org.oscim.core.MapPosition;
@@ -40,26 +39,64 @@ public class TestLineOverlay extends RenderOverlay {
super(mapView);
}
- private final float[] box = {
- // pos dir len
- 0, 0, 0, 0, // start offset
+ // Interleave two quads to be able to use vertices
+ // twice. pos0 and pos1 use the same vertex array
+ // where pos1 is off-setted by one vertex. The
+ // vertex shader will use pos0 when the vertexId
+ // is even, pos1 when the Id is odd.
+ //
+ // As there is no gl_VertexId in gles 2.0 an
+ // additional 'flip' array is used.
+ // Depending on 'flip' extrusion is inverted.
+ //
+ // Indices and flip buffers can be static.
+ //
+ // First pass: using even vertex array positions
+ // (used vertices are in braces)
+ // vertex id 0, 1, 2, 3
+ // pos0 - (0) 1 (2) 3 -
+ // pos1 - (0) 1 (2) 3 -
+ // flip 0 1 0 1
+ //
+ // Second pass: using odd vertex array positions
+ // vertex id 0, 1, 2, 3
+ // pos0 - 0 (1) 2 (3) -
+ // pos1 - 0 (1) 2 (3) -
+ // flip 0 1 0 1
+ //
+ // Vertex layout:
+ // x/y pos[16][16], dir_x[8]|dir_y[8], start[4]|length[12]
+ // - 'direction' precision 1/16 maximum line width is 2*32
+ // - texture 'start' prescision 1
+ // -> max tex width is 32
+ // - segment 'length' prescision 1/4
+ // -> max line length is 2^12/4=1024
+ // - texture 'end' is 'length'-'start'
- -800f, 0f, 1, 0, // first
- 100f, 0f, 1, 0.25f, // third
- 0f, 0f, 1, 1, // second
- 800f, 0f, 1, 1, // fourth
+ private final short[] box = {
+ // '-' start
+ 0, 0, 0, 0,
+ // 0.
+ -800, 0, 255, 0,
+ // 2.
+ 100, 0, 255, 0,
+ // 1.
+ 0, 0, 255, 1,
+ // 3.
+ 800, 0, 255, 1,
- -800f, 200f, 1, 0, // first
- 0f, 200f, 1, 0.25f, // third
- 0f, 200f, 1, 1, // second
- 800f, 200f, 1, 1, // fourth
+ -800, 200, 127, 0,
+ 0, 200, 127, 0,
+ 0, 200, 127, 1,
+ 800, 200, 127, 1,
- -800f, 400f, 1, 0, // first
- 0f, 400f, 1, 0.25f, // third
- 0f, 400f, 1, 1, // second
- 800f, 400f, 1, 1, // fourth
+ -800, 400, 255, 0,
+ 0, 400, 255, 0,
+ 0, 400, 255, 1,
+ 800, 400, 255, 1,
- 0, 0, 0, 0, // end
+ // '-' end
+ 0, 0, 0, 0,
};
private final short[] indices = {
@@ -90,12 +127,16 @@ public class TestLineOverlay extends RenderOverlay {
+ "attribute vec4 a_pos1;"
+ "attribute float a_flip;"
+ "varying vec4 color;"
+ + "const float ff = 256.0;"
+ + "const float ffff = 65536.0;"
+ "void main() {"
+ " if (a_flip == 0.0){"
- + " gl_Position = u_mvp * vec4(a_pos0.x, a_pos0.y + a_pos0.z * 100.0, 0.0, 1.0);"
+ + " vec2 dir = vec2((a_pos0.z / ffff), fract(a_pos0.z/ff))*64.0;"
+ + " gl_Position = u_mvp * vec4(a_pos0.xy + dir, 0.0, 1.0);"
+ " color = vec4(0.0,1.0,a_pos0.w,1.0);"
+ " }else {"
- + " gl_Position = u_mvp * vec4(a_pos1.x, a_pos1.y - a_pos1.z * 100.0, 0.0, 1.0);"
+ + " vec2 dir = vec2((a_pos1.z / ffff), fract(a_pos1.z/ff))*64.0;"
+ + " gl_Position = u_mvp * vec4(a_pos1.xy - dir, 0.0, 1.0);"
+ " color = vec4(1.0,0.5,a_pos1.w,1.0);"
+ "}}";
@@ -147,11 +188,11 @@ public class TestLineOverlay extends RenderOverlay {
GLES20.glBufferData(GLES20.GL_ELEMENT_ARRAY_BUFFER, 18 * 2, sbuf, GLES20.GL_STATIC_DRAW);
GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, 0);
- FloatBuffer fbuf = buf.asFloatBuffer();
- fbuf.put(box);
- fbuf.flip();
+ sbuf.clear();
+ sbuf.put(box);
+ sbuf.flip();
GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, mVertexBufferID);
- GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, 56 * 4, fbuf, GLES20.GL_STATIC_DRAW);
+ GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, 56 * 2, sbuf, GLES20.GL_STATIC_DRAW);
buf.clear();
buf.put(flip);
@@ -189,13 +230,13 @@ public class TestLineOverlay extends RenderOverlay {
GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, mVertexBufferID);
- GLES20.glVertexAttribPointer(htestVertexPosition0, 4, GLES20.GL_FLOAT, false, 0, 16);
- GLES20.glVertexAttribPointer(htestVertexPosition1, 4, GLES20.GL_FLOAT, false, 0, 0);
+ GLES20.glVertexAttribPointer(htestVertexPosition0, 4, GLES20.GL_SHORT, false, 0, 8);
+ GLES20.glVertexAttribPointer(htestVertexPosition1, 4, GLES20.GL_SHORT, false, 0, 0);
GLES20.glUniform4f(htestColor, 0.5f, 0.5f, 1.0f, 1.0f);
GLES20.glDrawElements(GLES20.GL_TRIANGLES, 18, GLES20.GL_UNSIGNED_SHORT, 0);
- GLES20.glVertexAttribPointer(htestVertexPosition0, 4, GLES20.GL_FLOAT, false, 0, 32);
- GLES20.glVertexAttribPointer(htestVertexPosition1, 4, GLES20.GL_FLOAT, false, 0, 16);
+ GLES20.glVertexAttribPointer(htestVertexPosition0, 4, GLES20.GL_SHORT, false, 0, 16);
+ GLES20.glVertexAttribPointer(htestVertexPosition1, 4, GLES20.GL_SHORT, false, 0, 8);
GLES20.glUniform4f(htestColor, 0.5f, 1.0f, 0.5f, 1.0f);
GLES20.glDrawElements(GLES20.GL_TRIANGLES, 18, GLES20.GL_UNSIGNED_SHORT, 0);
@@ -209,8 +250,6 @@ public class TestLineOverlay extends RenderOverlay {
@Override
protected void setMatrix(MapPosition curPos, float[] matrix) {
- // TODO if oPos == curPos this could be simplified
-
MapPosition oPos = mMapPosition;
byte z = oPos.zoomLevel;