我已经创造了一个立方体，它的旋转非常完美。我的任务是你点击哪个旋转方块。例如，如果你点击立方体表面的红色，我会赢，但我找不到立方体点击的表面视图，
编辑
我想要接触的表面。
这是我的渲染器代码：
public void onDrawFrame(GL10 arg0) {
// GLES20.glEnable(GLES20.GL_TEXTURE_CUBE_MAP);
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
GLES20.glUseProgram(iProgId);
cubeBuffer.position(0);
GLES20.glVertexAttribPointer(iPosition, 3, GLES20.GL_FLOAT, false, 0, cubeBuffer);
GLES20.glEnableVertexAttribArray(iPosition);
texBuffer.position(0);
GLES20.glVertexAttribPointer(iTexCoords, 3, GLES20.GL_FLOAT, false, 0, texBuffer);
GLES20.glEnableVertexAttribArray(iTexCoords);
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
GLES20.glBindTexture(GLES20.GL_TEXTURE_CUBE_MAP, iTexId);
GLES20.glUniform1i(iTexLoc, 0);
// Draw a cube.
// Translate the cube into the screen.
Matrix.setIdentityM(m_fIdentity, 0);
// Matrix.translateM(m_fIdentity, 0, 0.0f, 0.8f, -3.5f);
// Set a matrix that contains the current rotation.
Matrix.setIdentityM(mCurrentRotation, 0);
Matrix.rotateM(mCurrentRotation, 0, mDeltaX, 1.0f, 0.0f, 0.0f);
Matrix.rotateM(mCurrentRotation, 0, mDeltaY, 0.0f, 1.0f, 0.0f);
Matrix.rotateM(mCurrentRotation, 0, mDeltaZ, 0.0f, 0.0f, 1.0f);
mDeltaX = 0.0f;
mDeltaY = 0.0f;
mDeltaZ = 0.0f;
// Multiply the current rotation by the accumulated rotation, and then set the accumulated
// rotation to the result.
Matrix.multiplyMM(mTemporaryMatrix, 0, mCurrentRotation, 0, mAccumulatedRotation, 0);
System.arraycopy(mTemporaryMatrix, 0, mAccumulatedRotation, 0, 16);
// Rotate the cube taking the overall rotation into account.
Matrix.multiplyMM(mTemporaryMatrix, 0, m_fIdentity, 0, mAccumulatedRotation, 0);
System.arraycopy(mTemporaryMatrix, 0, m_fIdentity, 0, 16);
Matrix.multiplyMM(m_fVPMatrix, 0, m_fViewMatrix, 0, m_fIdentity, 0);
Matrix.multiplyMM(m_fVPMatrix, 0, m_fProjMatrix, 0, m_fVPMatrix, 0);
Ray ray = null;
if (mDeltaX != -99) {
ray = new Ray(arg0, width, height, mDeltaX, mDeltaY);
}
mDeltaX = -99;
// Matrix.translateM(m_fVPMatrix, 0, 0, 0, 1);
GLES20.glUniformMatrix4fv(iVPMatrix, 1, false, m_fVPMatrix, 0);
GLES20.glDrawElements(GLES20.GL_TRIANGLES, 36, GLES20.GL_UNSIGNED_SHORT, indexBuffer);
// GLES20.glDisable(GLES20.GL_TEXTURE_CUBE_MAP);
}
最佳答案
有没有可能在opengl中得到立方体的哪个曲面？
在渲染中，场景中的每个对象通常由视图矩阵和投影矩阵进行变换。视图矩阵描述了从中查看场景的方向和位置，而投影矩阵描述了从场景的三维点到视口的二维点的映射。投影矩阵从视图空间转换到剪辑空间，剪辑空间中的坐标通过与剪辑坐标的w分量相除，转换为（-1，-1，-1）到（1，1，1）范围内的标准化设备坐标（ndc）。
如果必须通过在视图端口上选择一个点来找到场景表面上的一个点，则必须找到一种方法来执行相反的操作。
识别物体表面的一种常用方法是用一个起点和一个方向来定义一条射线，并找到最先被射线击中的表面。视线就是这样的光线，因为它有一个起点和一个方向，但是如何根据视线定义光线取决于场景的投影类型。
当atOrthographic Projection时，眼睛空间中的坐标线性映射到标准化设备坐标，而atPerspective Projection时，相机截锥（截断的金字塔）中的眼睛空间坐标映射到立方体（标准化设备坐标）。
在这两种情况下，首先必须将视口位置转换为规格化（XY）设备坐标，范围从（-1，-1）到（1,1）。这是一个简单的线性映射：
w = with of the viewport
h = height of the viewport
x = X position of the mouse
y = Y position ot the mouse
ndc_x = 2.0 * x/w - 1.0;
ndc_y = 1.0 - 2.0 * y/h; // invert Y axis
在视图空间中的正交投影处定义视线
光线的起始点可以通过使用反向投影矩阵在近平面（z=0）上以标准化设备坐标变换视口中的点来计算。
R0_view = inverse( projection-matrix ) * (ndc_x, ndc_y, 0.0, 1.0)
视线的方向是进入观察端口（0，0，-1）的方向。
D_view = (0.0, 0.0, -1.0)
在视图空间中的透视投影处定义视线
视线的起点是相机的位置，在视图空间中是（0，0，0）。
R0_view = (0.0, 0.0, 0.0)
视线的方向可以通过在标准化设备坐标系中转换光线上的任何点，通过反投影矩阵来计算。
D_view = normalize( inverse( projection-matrix ) * (ndc_x, ndc_y, 0.0, 1.0) )
从视图坐标转换为世界坐标
要从视图空间转换到世界空间，视图空间坐标必须通过逆视图矩阵进行转换。
R0_world = inverse( view-matrix ) * R0_view
R1_world = inverse( view-matrix ) * (R0_view + D_view)
D_world = normalize(R1_world - R0_world)
找到光线与基本体的交点
要找到被光线击中的曲面，必须计算每个曲面（基本体）与光线的交点和光线的起点的距离。击中距离（射线方向）最小的曲面。
要查找光线与三角形基本体相交点的距离，必须执行以下步骤：
找到由三角形基本体的3个点定义的光线和平面的交点。
计算交点和光线起点之间的距离。
测试交点是否在光线的方向上（不是在相反的方向上）
测试交点是否在三角形轮廓内或三角形轮廓上。
找到交点和交点距离：
平面由范数向量（
NV）和平面上的点（P0）定义。如果三角形是由3个点A、B和C给出的，则平面的计算如下：P0 = A
NV = normalize( cross( B-A, C-A ) )
射线与平面的交线是通过代入射线方程来计算的
P_isect = dist * D + R0进入平面方程。如下：
P_isect = R0 + D * dist_isect
dist_isect = dot( P0 - R0, NV ) / dot( D, NV )
测试交点是否在光线方向：
如果距离大于或等于0.0，则交点在射线方向上。
测试交点是否在三角形轮廓上
要查明，如果一个点位于三角形内部，则必须进行测试，如果从一个角点到交点的直线位于连接到该角点的“到”腿之间：
bool PointInOrOn( P1, P2, A, B )
{
CP1 = cross( B - A, P1 - A )
CP2 = cross( B - A, P2 - A )
return dot( CP1, CP2 ) >= 0
}
bool PointInOrOnTriangle( P, A, B, C )
{
return PointInOrOn( P, A, B, C ) &&
PointInOrOn( P, B, C, A ) &&
PointInOrOn( P, C, A, B )
}
为了解决这个问题，下列问题的答案也会引起人们的兴趣：
How to recover view space position given view space depth value and ndc xy
Mouse picking miss
How to render depth linearly in modern OpenGL with gl_FragCoord.z in fragment shader?
Ray Sphere Intersections in OpenGL
请参阅WebGL示例，该示例演示了算法：
glArrayType = typeof Float32Array !="undefined" ? Float32Array : ( typeof WebGLFloatArray != "undefined" ? WebGLFloatArray : Array );
function IdentityMat44() {
var m = new glArrayType(16);
m[0] = 1; m[1] = 0; m[2] = 0; m[3] = 0;
m[4] = 0; m[5] = 1; m[6] = 0; m[7] = 0;
m[8] = 0; m[9] = 0; m[10] = 1; m[11] = 0;
m[12] = 0; m[13] = 0; m[14] = 0; m[15] = 1;
return m;
};
function RotateAxis(matA, angRad, axis) {
var aMap = [ [1, 2], [2, 0], [0, 1] ];
var a0 = aMap[axis][0], a1 = aMap[axis][1];
var sinAng = Math.sin(angRad), cosAng = Math.cos(angRad);
var matB = new glArrayType(16);
for ( var i = 0; i < 16; ++ i ) matB[i] = matA[i];
for ( var i = 0; i < 3; ++ i ) {
matB[a0*4+i] = matA[a0*4+i] * cosAng + matA[a1*4+i] * sinAng;
matB[a1*4+i] = matA[a0*4+i] * -sinAng + matA[a1*4+i] * cosAng;
}
return matB;
}
function Cross( a, b ) { return [ a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0], 0.0 ]; }
function Dot( a, b ) { return a[0]*b[0] + a[1]*b[1] + a[2]*b[2]; }
function Normalize( v ) {
var len = Math.sqrt( v[0] * v[0] + v[1] * v[1] + v[2] * v[2] );
return [ v[0] / len, v[1] / len, v[2] / len ];
}
function PointInOrOn( P1, P2, A, B )
{
CP1 = Cross( [ B[0]-A[0], B[1]-A[1], B[2]-A[2] ], [ P1[0]-A[0], P1[1]-A[1], P1[2]-A[2] ] )
CP2 = Cross( [ B[0]-A[0], B[1]-A[1], B[2]-A[2] ], [ P2[0]-A[0], P2[1]-A[1], P2[2]-A[2] ] )
return Dot( CP1, CP2 ) >= 0;
}
function PointInOrOnTriangle( P, A, B, C )
{
var isInA = PointInOrOn( P, A, B, C );
var isInB = PointInOrOn( P, B, C, A );
var isInC = PointInOrOn( P, C, A, B );
return isInA && isInB && isInC;
}
vec4_add = function( a, b ) { return [ a[0]+b[0], a[1]+b[1], a[2]+b[2], a[3]+b[3] ]; }
vec4_sub = function( a, b ) { return [ a[0]-b[0], a[1]-b[1], a[2]-b[2], a[3]-b[3] ]; }
vec4_mul = function( a, b ) { return [ a[0]*b[0], a[1]*b[1], a[2]*b[2], a[3]*b[3] ]; }
vec4_scale = function( a, s ) { return [ a[0]*s, a[1]*s, a[2]*s, a[3]*s ]; }
mat44_inverse = function( m ) {
var Coef00 = m[2*4+2] * m[3*4+3] - m[3*4+2] * m[2*4+3];
var Coef02 = m[1*4+2] * m[3*4+3] - m[3*4+2] * m[1*4+3];
var Coef03 = m[1*4+2] * m[2*4+3] - m[2*4+2] * m[1*4+3];
var Coef04 = m[2*4+1] * m[3*4+3] - m[3*4+1] * m[2*4+3];
var Coef06 = m[1*4+1] * m[3*4+3] - m[3*4+1] * m[1*4+3];
var Coef07 = m[1*4+1] * m[2*4+3] - m[2*4+1] * m[1*4+3];
var Coef08 = m[2*4+1] * m[3*4+2] - m[3*4+1] * m[2*4+2];
var Coef10 = m[1*4+1] * m[3*4+2] - m[3*4+1] * m[1*4+2];
var Coef11 = m[1*4+1] * m[2*4+2] - m[2*4+1] * m[1*4+2];
var Coef12 = m[2*4+0] * m[3*4+3] - m[3*4+0] * m[2*4+3];
var Coef14 = m[1*4+0] * m[3*4+3] - m[3*4+0] * m[1*4+3];
var Coef15 = m[1*4+0] * m[2*4+3] - m[2*4+0] * m[1*4+3];
var Coef16 = m[2*4+0] * m[3*4+2] - m[3*4+0] * m[2*4+2];
var Coef18 = m[1*4+0] * m[3*4+2] - m[3*4+0] * m[1*4+2];
var Coef19 = m[1*4+0] * m[2*4+2] - m[2*4+0] * m[1*4+2];
var Coef20 = m[2*4+0] * m[3*4+1] - m[3*4+0] * m[2*4+1];
var Coef22 = m[1*4+0] * m[3*4+1] - m[3*4+0] * m[1*4+1];
var Coef23 = m[1*4+0] * m[2*4+1] - m[2*4+0] * m[1*4+1];
var Fac0 = [Coef00, Coef00, Coef02, Coef03];
var Fac1 = [Coef04, Coef04, Coef06, Coef07];
var Fac2 = [Coef08, Coef08, Coef10, Coef11];
var Fac3 = [Coef12, Coef12, Coef14, Coef15];
var Fac4 = [Coef16, Coef16, Coef18, Coef19];
var Fac5 = [Coef20, Coef20, Coef22, Coef23];
var Vec0 = [ m[1*4+0], m[0*4+0], m[0*4+0], m[0*4+0] ];
var Vec1 = [ m[1*4+1], m[0*4+1], m[0*4+1], m[0*4+1] ];
var Vec2 = [ m[1*4+2], m[0*4+2], m[0*4+2], m[0*4+2] ];
var Vec3 = [ m[1*4+3], m[0*4+3], m[0*4+3], m[0*4+3] ];
var Inv0 = vec4_add( vec4_sub( vec4_mul(Vec1, Fac0), vec4_mul(Vec2, Fac1) ), vec4_mul( Vec3, Fac2 ) );
var Inv1 = vec4_add( vec4_sub( vec4_mul(Vec0, Fac0), vec4_mul(Vec2, Fac3) ), vec4_mul( Vec3, Fac4 ) );
var Inv2 = vec4_add( vec4_sub( vec4_mul(Vec0, Fac1), vec4_mul(Vec1, Fac3) ), vec4_mul( Vec3, Fac5 ) );
var Inv3 = vec4_add( vec4_sub( vec4_mul(Vec0, Fac2), vec4_mul(Vec1, Fac4) ), vec4_mul( Vec2, Fac5 ) );
var SignA = [+1.0, -1.0, +1.0, -1.0];
var SignB = [-1.0, +1.0, -1.0, +1.0];
var Inverse = [ vec4_mul(Inv0, SignA), vec4_mul(Inv1, SignB), vec4_mul(Inv2, SignA), vec4_mul(Inv3, SignB) ];
var Row0 = [Inverse[0][0], Inverse[1][0], Inverse[2][0], Inverse[3][0] ];
var Dot0 = [Row0[0], Row0[1], Row0[2], Row0[3] ];
Dot0 = vec4_mul( Dot0, [ m[0], m[1], m[2], m[3] ] );
var Dot1 = (Dot0[0] + Dot0[1]) + (Dot0[2] + Dot0[3]);
var OneOverDeterminant = 1 / Dot1;
var res = IdentityMat44();
for ( var inx1 = 0; inx1 < 4; inx1 ++ ) {
for ( var inx2 = 0; inx2 < 4; inx2 ++ )
res[inx1*4+inx2] = Inverse[inx1][inx2] * OneOverDeterminant;
}
return res;
}
Transform = function(vec, mat) {
var h = [
vec[0] * mat[0*4+0] + vec[1] * mat[1*4+0] + vec[2] * mat[2*4+0] + mat[3*4+0],
vec[0] * mat[0*4+1] + vec[1] * mat[1*4+1] + vec[2] * mat[2*4+1] + mat[3*4+1],
vec[0] * mat[0*4+2] + vec[1] * mat[1*4+2] + vec[2] * mat[2*4+2] + mat[3*4+2],
vec[0] * mat[0*4+3] + vec[1] * mat[1*4+3] + vec[2] * mat[2*4+3] + mat[3*4+3] ]
if ( h[3] == 0.0 )
return [0, 0, 0]
return [ h[0]/h[3], h[1]/h[3], h[2]/h[3] ];
}
var Camera = {};
Camera.create = function() {
this.pos = [0, 3, 0.0];
this.target = [0, 0, 0];
this.up = [0, 0, 1];
this.fov_y = 90;
this.vp = [800, 600];
this.near = 0.5;
this.far = 100.0;
}
Camera.Perspective = function() {
var fn = this.far + this.near;
var f_n = this.far - this.near;
var r = this.vp[0] / this.vp[1];
var t = 1 / Math.tan( Math.PI * this.fov_y / 360 );
var m = IdentityMat44();
m[0] = t/r; m[1] = 0; m[2] = 0; m[3] = 0;
m[4] = 0; m[5] = t; m[6] = 0; m[7] = 0;
m[8] = 0; m[9] = 0; m[10] = -fn / f_n; m[11] = -1;
m[12] = 0; m[13] = 0; m[14] = -2 * this.far * this.near / f_n; m[15] = 0;
return m;
}
Camera.LookAt = function() {
var mz = Normalize( [ this.pos[0]-this.target[0], this.pos[1]-this.target[1], this.pos[2]-this.target[2] ] );
var mx = Normalize( Cross( this.up, mz ) );
var my = Normalize( Cross( mz, mx ) );
var tx = Dot( mx, this.pos );
var ty = Dot( my, this.pos );
var tz = Dot( [-mz[0], -mz[1], -mz[2]], this.pos );
var m = IdentityMat44();
m[0] = mx[0]; m[1] = my[0]; m[2] = mz[0]; m[3] = 0;
m[4] = mx[1]; m[5] = my[1]; m[6] = mz[1]; m[7] = 0;
m[8] = mx[2]; m[9] = my[2]; m[10] = mz[2]; m[11] = 0;
m[12] = tx; m[13] = ty; m[14] = tz; m[15] = 1;
return m;
}
// shader program object
var ShaderProgram = {};
ShaderProgram.Create = function( shaderList, uniformNames ) {
var shaderObjs = [];
for ( var i_sh = 0; i_sh < shaderList.length; ++ i_sh ) {
var shderObj = this.CompileShader( shaderList[i_sh].source, shaderList[i_sh].stage );
if ( shderObj == 0 )
return 0;
shaderObjs.push( shderObj );
}
var progObj = this.LinkProgram( shaderObjs )
if ( progObj != 0 ) {
progObj.unifomLocation = {};
for ( var i_n = 0; i_n < uniformNames.length; ++ i_n ) {
var name = uniformNames[i_n];
progObj.unifomLocation[name] = gl.getUniformLocation( progObj, name );
}
}
return progObj;
}
ShaderProgram.Use = function( progObj ) { gl.useProgram( progObj ); }
ShaderProgram.SetUniformInt = function( progObj, name, val ) { gl.uniform1i( progObj.unifomLocation[name], val ); }
ShaderProgram.SetUniform2i = function( progObj, name, arr ) { gl.uniform2iv( progObj.unifomLocation[name], arr ); }
ShaderProgram.SetUniformFloat = function( progObj, name, val ) { gl.uniform1f( progObj.unifomLocation[name], val ); }
ShaderProgram.SetUniform2f = function( progObj, name, arr ) { gl.uniform2fv( progObj.unifomLocation[name], arr ); }
ShaderProgram.SetUniform3f = function( progObj, name, arr ) { gl.uniform3fv( progObj.unifomLocation[name], arr ); }
ShaderProgram.SetUniformMat44 = function( progObj, name, mat ) { gl.uniformMatrix4fv( progObj.unifomLocation[name], false, mat ); }
ShaderProgram.CompileShader = function( source, shaderStage ) {
var shaderScript = document.getElementById(source);
if (shaderScript) {
source = "";
var node = shaderScript.firstChild;
while (node) {
if (node.nodeType == 3) source += node.textContent;
node = node.nextSibling;
}
}
var shaderObj = gl.createShader( shaderStage );
gl.shaderSource( shaderObj, source );
gl.compileShader( shaderObj );
var status = gl.getShaderParameter( shaderObj, gl.COMPILE_STATUS );
if ( !status ) alert(gl.getShaderInfoLog(shaderObj));
return status ? shaderObj : 0;
}
ShaderProgram.LinkProgram = function( shaderObjs ) {
var prog = gl.createProgram();
for ( var i_sh = 0; i_sh < shaderObjs.length; ++ i_sh )
gl.attachShader( prog, shaderObjs[i_sh] );
gl.linkProgram( prog );
status = gl.getProgramParameter( prog, gl.LINK_STATUS );
if ( !status ) alert("Could not initialise shaders");
gl.useProgram( null );
return status ? prog : 0;
}
function drawScene(){
var canvas = document.getElementById( "ogl-canvas" );
Camera.create();
Camera.vp = [canvas.width, canvas.height];
var currentTime = Date.now();
var deltaMS = currentTime - startTime;
gl.viewport( 0, 0, canvas.width, canvas.height );
gl.enable( gl.DEPTH_TEST );
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
var prjMat = Camera.Perspective();
var viewMat = Camera.LookAt();
// set up draw shader
ShaderProgram.Use( progDraw );
ShaderProgram.SetUniformMat44( progDraw, "u_projectionMat44", prjMat );
ShaderProgram.SetUniformMat44( progDraw, "u_viewMat44", viewMat );
var modelMat = IdentityMat44()
modelMat = RotateAxis( modelMat, CalcAng( currentTime, 13.0 ), 0 );
modelMat = RotateAxis( modelMat, CalcAng( currentTime, 17.0 ), 1 );
ShaderProgram.SetUniformMat44( progDraw, "u_modelMat44", modelMat );
// draw scene
bufObj = bufCube;
gl.enableVertexAttribArray( progDraw.inPos );
gl.enableVertexAttribArray( progDraw.inCol );
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.pos );
gl.vertexAttribPointer( progDraw.inPos, 3, gl.FLOAT, false, 0, 0 );
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.col );
gl.vertexAttribPointer( progDraw.inCol, 3, gl.FLOAT, false, 0, 0 );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufObj.inx );
gl.drawElements( gl.TRIANGLES, bufObj.inxLen, gl.UNSIGNED_SHORT, 0 );
gl.disableVertexAttribArray( progDraw.pos );
gl.disableVertexAttribArray( progDraw.col );
var newColor = "#000000";
var pos = [-1, -1];
if (mousePos[0] > 0 && mousePos[1] > 0 ) {
var pos = [2.0 * mousePos[0] / canvas.width - 1.0, 1.0 - 2.0 * mousePos[1] / canvas.height];
var invPrjMat = mat44_inverse( prjMat )
var invViewMat = mat44_inverse( viewMat )
var invModelMat = mat44_inverse( modelMat )
var viewP1 = Transform([pos[0],pos[1],-1.0], invPrjMat);
var R0 = Transform(Transform([0,0,0], invViewMat), invModelMat);
var R1 = Transform(Transform(viewP1, invViewMat), invModelMat);
var D = Normalize( [ R1[0]-R0[0], R1[1]-R0[1], R1[2]-R0[2] ] );
var minDist = 100000;
for ( it = 0; it < cubeInxData.length; it = it + 3 )
{
var trI = [ cubeInxData[it+0], cubeInxData[it+1], cubeInxData[it+2] ]
var A = [ cubePosData[trI[0]*3+0], cubePosData[trI[0]*3+1], cubePosData[trI[0]*3+2] ];
var B = [ cubePosData[trI[1]*3+0], cubePosData[trI[1]*3+1], cubePosData[trI[1]*3+2] ];
var C = [ cubePosData[trI[2]*3+0], cubePosData[trI[2]*3+1], cubePosData[trI[2]*3+2] ];
P0 = A;
NV = Cross( [ B[0]-A[0], B[1]-A[1], B[2]-A[2] ], [ C[0]-A[0], C[1]-A[1], C[2]-A[2] ] );
NV = Normalize( NV );
dist_isect = Dot( [ P0[0]-R0[0], P0[1]-R0[1], P0[2]-R0[2] ], NV ) / Dot( D, NV );
if ( dist_isect < 0.0 )
continue;
P_isect = [ R0[0] + D[0] * dist_isect, R0[1] + D[1] * dist_isect, R0[2] + D[2] * dist_isect ];
if ( PointInOrOnTriangle( P_isect, A, B, C ) )
{
var col = [
Math.floor(cubeColData[trI[0]*3+0]*255),
Math.floor(cubeColData[trI[0]*3+1]*255),
Math.floor(cubeColData[trI[0]*3+2]*255) ];
h0 = col[0].toString(16); if( h0.length < 2 ) h0 = "0" + h0;
h1 = col[1].toString(16); if( h1.length < 2 ) h1 = "0" + h1;
h2 = col[2].toString(16); if( h2.length < 2 ) h2 = "0" + h2;
if ( dist_isect < minDist ) {
minDist = dist_isect;
newColor = "#" + h0 + h1 + h2;
}
}
}
}
document.getElementById( "color" ).value = newColor;
document.getElementById( "mouseX" ).innerHTML = pos[0];
document.getElementById( "mouseY" ).innerHTML = pos[1];
}
var startTime;
function Fract( val ) {
return val - Math.trunc( val );
}
function CalcAng( currentTime, intervall ) {
return Fract( (currentTime - startTime) / (1000*intervall) ) * 2.0 * Math.PI;
}
function CalcMove( currentTime, intervall, range ) {
var pos = self.Fract( (currentTime - startTime) / (1000*intervall) ) * 2.0
var pos = pos < 1.0 ? pos : (2.0-pos)
return range[0] + (range[1] - range[0]) * pos;
}
function EllipticalPosition( a, b, angRag ) {
var a_b = a * a - b * b
var ea = (a_b <= 0) ? 0 : Math.sqrt( a_b );
var eb = (a_b >= 0) ? 0 : Math.sqrt( -a_b );
return [ a * Math.sin( angRag ) - ea, b * Math.cos( angRag ) - eb, 0 ];
}
var mousePos = [-1, -1];
var sliderScale = 100.0
var gl;
var progDraw;
var bufCube = {};
var bufTorus = {};
var cubePosData = [];
var cubeColData = [];
var cubeInxData = [];
function sceneStart() {
var canvas = document.getElementById( "ogl-canvas");
var vp = [canvas.width, canvas.height];
gl = canvas.getContext( "experimental-webgl" );
if ( !gl )
return;
progDraw = ShaderProgram.Create(
[ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER }
],
[ "u_projectionMat44", "u_viewMat44", "u_modelMat44" ] );
progDraw.inPos = gl.getAttribLocation( progDraw, "inPos" );
progDraw.inCol = gl.getAttribLocation( progDraw, "inCol" );
if ( progDraw == 0 )
return;
// create cube
var cubePos = [
-1.0, -1.0, 1.0, 1.0, -1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0,
-1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0 ];
var cubeCol = [ 1.0, 0.0, 0.0, 1.0, 0.5, 0.0, 1.0, 0.0, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0 ];
var cubeHlpInx = [ 0, 1, 2, 3, 1, 5, 6, 2, 5, 4, 7, 6, 4, 0, 3, 7, 3, 2, 6, 7, 1, 0, 4, 5 ];
for ( var i = 0; i < cubeHlpInx.length; ++ i ) {
cubePosData.push( cubePos[cubeHlpInx[i]*3], cubePos[cubeHlpInx[i]*3+1], cubePos[cubeHlpInx[i]*3+2] );
}
for ( var is = 0; is < 6; ++ is ) {
for ( var ip = 0; ip < 4; ++ ip ) {
cubeColData.push( cubeCol[is*3], cubeCol[is*3+1], cubeCol[is*3+2] );
}
}
for ( var i = 0; i < cubeHlpInx.length; i += 4 ) {
cubeInxData.push( i, i+1, i+2, i, i+2, i+3 );
}
bufCube.pos = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, bufCube.pos );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( cubePosData ), gl.STATIC_DRAW );
bufCube.col = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, bufCube.col );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( cubeColData ), gl.STATIC_DRAW );
bufCube.inx = gl.createBuffer();
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufCube.inx );
gl.bufferData( gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( cubeInxData ), gl.STATIC_DRAW );
bufCube.inxLen = cubeInxData.length;
startTime = Date.now();
setInterval(drawScene, 50);
}
(function() {
document.onmousemove = handleMouseMove;
function handleMouseMove(event) {
var dot, eventDoc, doc, body, pageX, pageY;
event = event || window.event; // IE-ism
if (event.pageX == null && event.clientX != null) {
eventDoc = (event.target && event.target.ownerDocument) || document;
doc = eventDoc.documentElement;
body = eventDoc.body;
event.pageX = event.clientX +
(doc && doc.scrollLeft || body && body.scrollLeft || 0) -
(doc && doc.clientLeft || body && body.clientLeft || 0);
event.pageY = event.clientY +
(doc && doc.scrollTop || body && body.scrollTop || 0) -
(doc && doc.clientTop || body && body.clientTop || 0 );
}
var canvas = document.getElementById( "ogl-canvas");
var x = event.pageX - canvas.offsetLeft;
var y = event.pageY - canvas.offsetTop;
mousePos = [-1, -1];
if ( x >= 0 && x < canvas.width && y >= 0 && y < canvas.height ) {
mousePos = [x, y];
}
}
})();<script id="draw-shader-vs" type="x-shader/x-vertex">
precision mediump float;
attribute vec3 inPos;
attribute vec3 inCol;
varying vec3 vertCol;
uniform mat4 u_projectionMat44;
uniform mat4 u_viewMat44;
uniform mat4 u_modelMat44;
void main()
{
vertCol = inCol;
vec4 modelPos = u_modelMat44 * vec4( inPos, 1.0 );
vec4 viewPos = u_viewMat44 * modelPos;
gl_Position = u_projectionMat44 * viewPos;
}
</script>
<script id="draw-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vertCol;
void main()
{
gl_FragColor = vec4( vertCol.rgb, 1.0 );
}
</script>
<body onload="sceneStart();">
<div style="margin-left: 260px;">
<div style="float: right; width: 100%; background-color: #CCF;">
<form name="inputs">
<table>
<tr> <td> <input type="color" value="#000000" id="color" disabled></td> </tr>
<tr> <td> <span id="mouseX">0</span> </td> </tr>
<tr> <td> <span id="mouseY">0</span> </td> </tr>
</table>
</form>
</div>
<div style="float: right; width: 260px; margin-left: -260px;">
<canvas id="ogl-canvas" style="border: none;" width="256" height="256"></canvas>
</div>
<div style="clear: both;"></div>
</div>
</body>关于android - 是否有可能在OpenGL中点击多维数据集的哪个表面？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/45893277/