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我在這裏遇到問題。我建立了一個速度爲x和y的正方形彈丸，並通過像這樣設置頂點位置，將實際的方形繪製到位置。glRotate更改座標，以便矩形繪製旋轉的平面
代碼：
vertices.put(new float[] { x1, y1, 1, 1, 1, 1, 0.0f, 1.0f,
x2, y2, 1, 1, 1, 1, 1.0f, 1.0f,
x3, y3, 1, 1, 1, 1, 1.0f, 0.0f,
x4, y4, 1, 1, 1, 1, 0.0f, 0.0f });
// x y r g b A u|s v|t
，所有的X的是我通過在角落的位置
我再沿x & Y軸移動這個矩形（l2rArrow），並具有畫面後續它：
boolean hasTranslated = false;
if (!l2rArrow.isFired) { // if the arrow has not yet been fired we render it thus
gl.glPushMatrix(); //save our state
gl.glTranslatef(l2rArrow.GetToOriginX, l2rArrow.GetToOriginY, 0f); // translate to origin 0,0,0
gl.glRotatef(LBow.getAngle(), 0f, 0f, 1f); //rotate
gl.glTranslatef(-l2rArrow.GetToOriginX, -l2rArrow.GetToOriginY, 0f); // translate to where we want to draw it
texture.bind(gl, Texture.TEXTURE_L2RARROW);
mRect = new MeshRect(l2rArrow.getMyRect());
mRect.Draw(GL10.GL_TRIANGLES, gl);
gl.glPopMatrix(); //return to saved state
} else { // the arrow has been fired so we need to render it like this and have the "camera" follow it
hasTranslated = true;
gl.glPushMatrix();
gl.glLoadIdentity();
float camX = (float) ((l2rArrow.startX - l2rArrow.PosX));
float camY = (float) ((l2rArrow.startY - l2rArrow.PosY));
if (camY > 0) { camY = 0;}
if (camX < -4800) { camX = -4800;}
gl.glTranslatef(camX, camY,0f);
l2rArrow.Update(deltaTime);
texture.bind(gl, Texture.TEXTURE_L2RARROW);
mRect = new MeshRect(l2rArrow.getMyRect());
mRect.Draw(GL10.GL_TRIANGLES, gl);
if (l2rArrow.hasCollided) {
//run collision code for detecting a hit and ending turn
}
}
這也適用。當射彈被射擊時，我們會完全遵循它。現在，儘管我想讓箭頭指向箭頭正在傳播的角度。所以我需要在中途轉動箭頭。我嘗試將這個箭頭轉換回0,0旋轉它，然後把它放回去，但是當我把箭頭放回去時，它會繪製旋轉平面的座標。
} else {
hasTranslated = true;
gl.glPushMatrix();
gl.glLoadIdentity();
float camX = (float) ((l2rArrow.startX - l2rArrow.PosX));
float camY = (float) ((l2rArrow.startY - l2rArrow.PosY));
if (camY > 0) { camY = 0;}
if (camX < -4800) { camX = -4800;}
gl.glTranslatef(camX, camY,0f);
gl.glPushMatrix();
gl.glTranslatef(l2rArrow.GetToOriginX, l2rArrow.GetToOriginY, 0f); // translate to origin 0,0,0
gl.glRotatef((float) l2rArrow.getAngle(), 0f, 0f, 1f); //rotate
gl.glTranslatef(-l2rArrow.GetToOriginX, -l2rArrow.GetToOriginY, 0f);
l2rArrow.Update(deltaTime);
texture.bind(gl, Texture.TEXTURE_L2RARROW);
mRect = new MeshRect(l2rArrow.getMyRect());
mRect.Draw(GL10.GL_TRIANGLES, gl);
gl.glPopMatrix();
if (l2rArrow.hasCollided) {
//run collision code for detecting a hit and ending turn
}
}
我明白這一點。如何旋轉箭頭，然後將其移回非旋轉平面上的位置？
當Y = 0時，箭頭休息，而現在Y = 0以旋轉角度運行。