public Square ()
{
// initialize vertex byte buffer for shape coordinates
ByteBuffer bb = ByteBuffer.AllocateDirect (
// (# of coordinate values * 4 bytes per float)
squareCoords.Length * 4);
bb.Order (ByteOrder.NativeOrder ());
vertexBuffer = bb.AsFloatBuffer ();
vertexBuffer.Put (squareCoords);
vertexBuffer.Position (0);
// initialize byte buffer for the draw list
ByteBuffer dlb = ByteBuffer.AllocateDirect (
// (# of coordinate values * 2 bytes per short)
drawOrder.Length * 2);
dlb.Order (ByteOrder.NativeOrder ());
drawListBuffer = dlb.AsShortBuffer ();
drawListBuffer.Put (drawOrder);
drawListBuffer.Position (0);
// prepare shaders and OpenGL program
int vertexShader = MyGLRenderer.LoadShader (GLES20.GlVertexShader,
vertexShaderCode);
int fragmentShader = MyGLRenderer.LoadShader (GLES20.GlFragmentShader,
fragmentShaderCode);
mProgram = GLES20.GlCreateProgram (); // create empty OpenGL Program
GLES20.GlAttachShader (mProgram, vertexShader); // add the vertex shader to program
GLES20.GlAttachShader (mProgram, fragmentShader); // add the fragment shader to program
GLES20.GlLinkProgram (mProgram); // create OpenGL program executables
}
/**
* Updates the plane model transform matrix and extents.
*/
private void updatePlaneParameters(float[] planeMatrix, float extentX, float extentZ,
FloatBuffer boundary)
{
Array.Copy(planeMatrix, 0, mModelMatrix, 0, 16);
if (boundary == null)
{
mVertexBuffer.Limit(0);
mIndexBuffer.Limit(0);
return;
}
// Generate a new set of vertices and a corresponding triangle strip index set so that
// the plane boundary polygon has a fading edge. This is done by making a copy of the
// boundary polygon vertices and scaling it down around center to push it inwards. Then
// the index buffer is setup accordingly.
boundary.Rewind();
int boundaryVertices = boundary.Limit() / 2;
int numVertices;
int numIndices;
numVertices = boundaryVertices * VERTS_PER_BOUNDARY_VERT;
// drawn as GL_TRIANGLE_STRIP with 3n-2 triangles (n-2 for fill, 2n for perimeter).
numIndices = boundaryVertices * INDICES_PER_BOUNDARY_VERT;
if (mVertexBuffer.Capacity() < numVertices * COORDS_PER_VERTEX)
{
int size = mVertexBuffer.Capacity();
while (size < numVertices * COORDS_PER_VERTEX)
{
size *= 2;
}
mVertexBuffer = ByteBuffer.AllocateDirect(BYTES_PER_FLOAT * size)
.Order(ByteOrder.NativeOrder()).AsFloatBuffer();
}
mVertexBuffer.Rewind();
mVertexBuffer.Limit(numVertices * COORDS_PER_VERTEX);
if (mIndexBuffer.Capacity() < numIndices)
{
int size = mIndexBuffer.Capacity();
while (size < numIndices)
{
size *= 2;
}
mIndexBuffer = ByteBuffer.AllocateDirect(BYTES_PER_SHORT * size)
.Order(ByteOrder.NativeOrder()).AsShortBuffer();
}
mIndexBuffer.Rewind();
mIndexBuffer.Limit(numIndices);
// Note: when either dimension of the bounding box is smaller than 2*FADE_RADIUS_M we
// generate a bunch of 0-area triangles. These don't get rendered though so it works
// out ok.
float xScale = Math.Max((extentX - 2 * FADE_RADIUS_M) / extentX, 0.0f);
float zScale = Math.Max((extentZ - 2 * FADE_RADIUS_M) / extentZ, 0.0f);
while (boundary.HasRemaining)
{
float x = boundary.Get();
float z = boundary.Get();
mVertexBuffer.Put(x);
mVertexBuffer.Put(z);
mVertexBuffer.Put(0.0f);
mVertexBuffer.Put(x * xScale);
mVertexBuffer.Put(z * zScale);
mVertexBuffer.Put(1.0f);
}
// step 1, perimeter
mIndexBuffer.Put((short)((boundaryVertices - 1) * 2));
for (int i = 0; i < boundaryVertices; ++i)
{
mIndexBuffer.Put((short)(i * 2));
mIndexBuffer.Put((short)(i * 2 + 1));
}
mIndexBuffer.Put((short)1);
// This leaves us on the interior edge of the perimeter between the inset vertices
// for boundary verts n-1 and 0.
// step 2, interior:
for (int i = 1; i < boundaryVertices / 2; ++i)
{
mIndexBuffer.Put((short)((boundaryVertices - 1 - i) * 2 + 1));
mIndexBuffer.Put((short)(i * 2 + 1));
}
if (boundaryVertices % 2 != 0)
{
mIndexBuffer.Put((short)((boundaryVertices / 2) * 2 + 1));
}
}
/**
* Creates and initializes OpenGL resources needed for rendering the model.
*
* @param context Context for loading the shader and below-named model and texture assets.
* @param objAssetName Name of the OBJ file containing the model geometry.
* @param diffuseTextureAssetName Name of the PNG file containing the diffuse texture map.
*/
public void CreateOnGlThread(Context context, string objAssetName, string diffuseTextureAssetName)
{
// Read the texture.
var textureBitmap = BitmapFactory.DecodeStream(context.Assets.Open(diffuseTextureAssetName));
GLES20.GlActiveTexture(GLES20.GlTexture0);
GLES20.GlGenTextures(mTextures.Length, mTextures, 0);
GLES20.GlBindTexture(GLES20.GlTexture2d, mTextures[0]);
GLES20.GlTexParameteri(GLES20.GlTexture2d,
GLES20.GlTextureMinFilter, GLES20.GlLinearMipmapLinear);
GLES20.GlTexParameteri(GLES20.GlTexture2d,
GLES20.GlTextureMagFilter, GLES20.GlLinear);
GLUtils.TexImage2D(GLES20.GlTexture2d, 0, textureBitmap, 0);
GLES20.GlGenerateMipmap(GLES20.GlTexture2d);
GLES20.GlBindTexture(GLES20.GlTexture2d, 0);
textureBitmap.Recycle();
ShaderUtil.CheckGLError(TAG, "Texture loading");
// Read the obj file.
var objInputStream = context.Assets.Open(objAssetName);
var obj = ObjReader.Read(objInputStream);
// Prepare the Obj so that its structure is suitable for
// rendering with OpenGL:
// 1. Triangulate it
// 2. Make sure that texture coordinates are not ambiguous
// 3. Make sure that normals are not ambiguous
// 4. Convert it to single-indexed data
obj = ObjUtils.ConvertToRenderable(obj);
// OpenGL does not use Java arrays. ByteBuffers are used instead to provide data in a format
// that OpenGL understands.
// Obtain the data from the OBJ, as direct buffers:
IntBuffer wideIndices = ObjData.GetFaceVertexIndices(obj, 3);
FloatBuffer vertices = ObjData.GetVertices(obj);
FloatBuffer texCoords = ObjData.GetTexCoords(obj, 2);
FloatBuffer normals = ObjData.GetNormals(obj);
// Convert int indices to shorts for GL ES 2.0 compatibility
ShortBuffer indices = ByteBuffer.AllocateDirect(2 * wideIndices.Limit())
.Order(ByteOrder.NativeOrder()).AsShortBuffer();
while (wideIndices.HasRemaining)
{
indices.Put((short)wideIndices.Get());
}
indices.Rewind();
var buffers = new int[2];
GLES20.GlGenBuffers(2, buffers, 0);
mVertexBufferId = buffers[0];
mIndexBufferId = buffers[1];
// Load vertex buffer
mVerticesBaseAddress = 0;
mTexCoordsBaseAddress = mVerticesBaseAddress + 4 * vertices.Limit();
mNormalsBaseAddress = mTexCoordsBaseAddress + 4 * texCoords.Limit();
int totalBytes = mNormalsBaseAddress + 4 * normals.Limit();
GLES20.GlBindBuffer(GLES20.GlArrayBuffer, mVertexBufferId);
GLES20.GlBufferData(GLES20.GlArrayBuffer, totalBytes, null, GLES20.GlStaticDraw);
GLES20.GlBufferSubData(
GLES20.GlArrayBuffer, mVerticesBaseAddress, 4 * vertices.Limit(), vertices);
GLES20.GlBufferSubData(
GLES20.GlArrayBuffer, mTexCoordsBaseAddress, 4 * texCoords.Limit(), texCoords);
GLES20.GlBufferSubData(
GLES20.GlArrayBuffer, mNormalsBaseAddress, 4 * normals.Limit(), normals);
GLES20.GlBindBuffer(GLES20.GlArrayBuffer, 0);
// Load index buffer
GLES20.GlBindBuffer(GLES20.GlElementArrayBuffer, mIndexBufferId);
mIndexCount = indices.Limit();
GLES20.GlBufferData(
GLES20.GlElementArrayBuffer, 2 * mIndexCount, indices, GLES20.GlStaticDraw);
GLES20.GlBindBuffer(GLES20.GlElementArrayBuffer, 0);
ShaderUtil.CheckGLError(TAG, "OBJ buffer load");
int vertexShader = ShaderUtil.LoadGLShader(TAG, context,
GLES20.GlVertexShader, Resource.Raw.object_vertex);
int fragmentShader = ShaderUtil.LoadGLShader(TAG, context,
GLES20.GlFragmentShader, Resource.Raw.object_fragment);
mProgram = GLES20.GlCreateProgram();
GLES20.GlAttachShader(mProgram, vertexShader);
GLES20.GlAttachShader(mProgram, fragmentShader);
GLES20.GlLinkProgram(mProgram);
GLES20.GlUseProgram(mProgram);
ShaderUtil.CheckGLError(TAG, "Program creation");
mModelViewUniform = GLES20.GlGetUniformLocation(mProgram, "u_ModelView");
mModelViewProjectionUniform =
GLES20.GlGetUniformLocation(mProgram, "u_ModelViewProjection");
mPositionAttribute = GLES20.GlGetAttribLocation(mProgram, "a_Position");
mNormalAttribute = GLES20.GlGetAttribLocation(mProgram, "a_Normal");
mTexCoordAttribute = GLES20.GlGetAttribLocation(mProgram, "a_TexCoord");
mTextureUniform = GLES20.GlGetUniformLocation(mProgram, "u_Texture");
mLightingParametersUniform = GLES20.GlGetUniformLocation(mProgram, "u_LightingParameters");
mMaterialParametersUniform = GLES20.GlGetUniformLocation(mProgram, "u_MaterialParameters");
ShaderUtil.CheckGLError(TAG, "Program parameters");
Android.Opengl.Matrix.SetIdentityM(mModelMatrix, 0);
}
public void SetIndices(short[] indices, int offset, int length)
{
_indices.Clear();
_indices.Put(indices, offset, length);
_indices.Flip();
}