关于ios：Swift inout参数性能

Swift inout parameter performance

我的表现很糟糕，速度很快(低fps，只有一些纹理被绘制)。在Android上的爪哇，我正在执行一批30到40倍的代码。我在.mm文件中有一些OpenGL的矩阵数学函数。我通过swift(桥接头)使用matrix.mm文件中的函数。这些矩阵操作的运行速度似乎比OpenGL Draw调用还要慢。完全相反，从我的Android版本。甚至OpenGL绘图调用似乎比Android慢3到4倍。应用程序上是否必须启用某个设置才能使其更快(关闭某些隐藏的调试设置或其他设置)？

matrix.mm函数(示例)

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+(void) translateM:(mFloat*) m mOffset:(int) mOffset x:(mFloat) x y:(mFloat) y z:(mFloat) z {
for (int i=0 ; i<4 ; i++) {
int mi = mOffset + i;
m[12 + mi] += m[mi] * x + m[4 + mi] * y + m[8 + mi] * z;
}
}

#define I(_i, _j) ((_j)+ 4*(_i))
+(void) multiplyMM:(mFloat*) result resultOffset:(int) resultOffset lhs:(const mFloat*) lhs lhsOffset:(int) lhsOffset rhs:(const mFloat*) rhs rhsOffset:(int) rhsOffset{
result += resultOffset;
lhs += lhsOffset;
rhs += rhsOffset;

for (int i=0 ; i<4 ; i++) {
const mFloat rhs_i0 = rhs[ I(i,0) ];
mFloat ri0 = lhs[ I(0,0) ] * rhs_i0;
mFloat ri1 = lhs[ I(0,1) ] * rhs_i0;
mFloat ri2 = lhs[ I(0,2) ] * rhs_i0;
mFloat ri3 = lhs[ I(0,3) ] * rhs_i0;
for (int j=1 ; j<4 ; j++) {
const mFloat rhs_ij = rhs[ I(i,j) ];
ri0 += lhs[ I(j,0) ] * rhs_ij;
ri1 += lhs[ I(j,1) ] * rhs_ij;
ri2 += lhs[ I(j,2) ] * rhs_ij;
ri3 += lhs[ I(j,3) ] * rhs_ij;
}
result[ I(i,0) ] = ri0;
result[ I(i,1) ] = ri1;
result[ I(i,2) ] = ri2;
result[ I(i,3) ] = ri3;
}
}

+(void) multiplyMV:(mFloat*) resultVec resultVecOffset:(int) resultVecOffset lhsMat:(const mFloat*) lhsMat lhsMatOffset:(int) lhsMatOffset rhsVec:(const mFloat*) rhsVec rhsVecOffsetint:(int) rhsVecOffset{

resultVec += resultVecOffset;
lhsMat += lhsMatOffset;
rhsVec += rhsVecOffset;

[Matrix mx4transform:rhsVec[0] y:rhsVec[1] z:rhsVec[2] w:rhsVec[3] pM:lhsMat pDest:resultVec];

}
+(void) setIdentityM:(mFloat*) sm smOffset:(int) smOffset {
for (int i=0 ; i<16 ; i++) {
sm[smOffset + i] = 0;
}
for(int i = 0; i < 16; i += 5) {
sm[smOffset + i] = 1.0f;
}
}

在swift中调用的矩阵函数(比android慢40倍)

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func draw(){
var s1:Double = Engine.getCurrentTimeMillis();

inPoint[2] = -1;
inPoint[3] = 1;

Matrix.setIdentityM(&mModelMatrix, smOffset: 0);
Matrix.translateM(&mModelMatrix, mOffset: 0, x: positionX, y: positionY, z: positionZ);
Matrix.rotateM(&mModelMatrix, mOffset: 0, a: angle, x: 0.0, y: 0.0, z: 1.0);

inPoint[0] = VERTEX_DATA[0];
inPoint[1] = VERTEX_DATA[1];
Matrix.multiplyMV(&outPoint, resultVecOffset: 0, lhsMat: mModelMatrix, lhsMatOffset: 0, rhsVec: inPoint, rhsVecOffsetint: 0);
rotatedPoints[0] = outPoint[0];
rotatedPoints[1] = outPoint[1];

inPoint[0] = VERTEX_DATA[4];
inPoint[1] = VERTEX_DATA[5];
Matrix.multiplyMV(&outPoint, resultVecOffset: 0, lhsMat: mModelMatrix, lhsMatOffset: 0, rhsVec: inPoint, rhsVecOffsetint: 0);
rotatedPoints[2] = outPoint[0];
rotatedPoints[3] = outPoint[1];

inPoint[0] = VERTEX_DATA[8];
inPoint[1] = VERTEX_DATA[9];
Matrix.multiplyMV(&outPoint, resultVecOffset: 0, lhsMat: mModelMatrix, lhsMatOffset: 0, rhsVec: inPoint, rhsVecOffsetint: 0);
rotatedPoints[4] = outPoint[0];
rotatedPoints[5] = outPoint[1];

inPoint[0] = VERTEX_DATA[12];
inPoint[1] = VERTEX_DATA[13];
Matrix.multiplyMV(&outPoint, resultVecOffset: 0, lhsMat: mModelMatrix, lhsMatOffset: 0, rhsVec: inPoint, rhsVecOffsetint: 0);
rotatedPoints[6] = outPoint[0];
rotatedPoints[7] = outPoint[1];
var s1End:Double = Engine.getCurrentTimeMillis() - s1;

if (isVisible()) {

test.drawCount++;

Matrix.multiplyMM(&mMVPMatrix, resultOffset: 0, lhs: mViewMatrix, lhsOffset: 0, rhs: mModelMatrix, rhsOffset: 0);

Matrix.multiplyMM(&mMVPMatrix, resultOffset: 0,
lhs: mProjectionMatrix, lhsOffset: 0, rhs: mMVPMatrix, rhsOffset: 0);

var s2:Double = Engine.getCurrentTimeMillis();
ResourceManager.props.textureShaderProgram.useProgram();
bindData(ResourceManager.props.textureShaderProgram);
ResourceManager.props.textureShaderProgram.setUniforms(mMVPMatrix, textureId: ResourceManager.getTexture(texture));

glDrawElements(GLenum(GL_TRIANGLES), GLsizei(indices.count), GLenum(GL_UNSIGNED_SHORT), indices);

var s2End = Engine.getCurrentTimeMillis() - s2;

println("Matrix: \(s1End) GL: \(s2End)" );

}
}