Issue with rendering...
Posted: Sun Oct 02, 2011 8:43 pm
I made the basis of a simple game, and I have run into a simple problem. In the game, there is a spaceship, it can move around, and shoot lasers, this is where the problem begins. Because the spaceship must rotate, the coordinates translate the spaceship to be center, then puts the center back into the top left corner so the lasers can be rendered, the problem is, that the lasers still appear to be affected by the earlier translation and rotation because the lasers will be off center and rotate with the ship. I know for certain that it's just a rendering problem, because the lasers still appear to get deleted when the numbers representing them leave the boundaries. I'll provide the code so you may be able to help me.
Code: Select all
width = love.graphics.getWidth()
height = love.graphics.getHeight()
xpos, ypos = width/2, height/2
xvel, yvel = 0, 0
rotation = 0
bounce = 0.01
friction = 1.0085
boost = 3000
lRTime = 60
laserReload = 0
laserInitVel = 15
laserNum = 0
lasers = {}
function love.update()
width = love.graphics.getWidth()
height = love.graphics.getHeight()
if love.keyboard.isDown("up") then
xvel = math.cos(math.rad(rotation))*5
yvel = math.sin(math.rad(rotation))*5
end
if love.keyboard.isDown("down") then
if boost > 0 then
xvel = math.cos(math.rad(rotation))*10
yvel = math.sin(math.rad(rotation))*10
boost = boost - 1
else
xvel = math.cos(math.rad(rotation))*5
yvel = math.sin(math.rad(rotation))*5
end
end
if love.keyboard.isDown("left") then
rotation = rotation - 1
end
if love.keyboard.isDown("right") then
rotation = rotation + 1
end
if love.keyboard.isDown(" ") then --Making a laser. Once a laser is made, it's given a position and a velocity
if laserReload <= 0 then
table.insert(lasers, (--[[["laser.."laserNum] = ]]{xpos+(math.cos(math.rad(rotation))*10),ypos+(math.sin(math.rad(rotation))*10), math.cos(math.rad(rotation))*laserInitVel, math.sin(math.rad(rotation))*laserInitVel}))
laserReload = laserReload + lRTime
end
end
--next part is simple collision st00f, temporary
if xpos-10 <= 0 then
xvel = xvel * -1 * bounce
xpos = 10
end
if xpos+10 >= width then
xvel = xvel * -1 * bounce
xpos = width-10
end
if ypos-10 <= 0 then
yvel = yvel * -1 * bounce
ypos = 10
end
if ypos+10 >= height then
yvel = yvel * -1 * bounce
ypos = height-10
end
if laserReload > 0 then
laserReload = laserReload - 1
end
for a, b in pairs(lasers) do--Keepin' those lasers moving. If they leave the
b[1] = b[1] + b[3]/10
b[2] = b[2] + b[4]/10
if b[1] >= width+10 or b[1] <= 0-10 or b[2] >= height+10 or b[2] <= 0-10 then
table.remove(lasers, a)
end
end
xpos = xpos + xvel/10
ypos = ypos + yvel/10
xvel = xvel/friction
yvel = yvel/friction
end
function love.draw()
love.graphics.setColor(255,63,0)
love.graphics.print("Boost Fuel: "..boost, 10, 100)
love.graphics.setColor(0,127,255)--From here...
love.graphics.translate(xpos, ypos)
love.graphics.rotate(math.rad(rotation+90))
love.graphics.polygon("fill", 0, -10, 10, 10, 0, 5, -10, 10)
love.graphics.setColor(255,255,255)
love.graphics.line(0, 5, 0, -10)--To here, components of the ship are rendered.
love.graphics.translate(0, 0)
love.graphics.rotate(math.rad(0))
for c, d in pairs(lasers) do--Rendering them lasers. Length affected by speed.
love.graphics.line(d[1]-d[3]/5, d[2]-d[4]/5, d[1]+d[3]/5, d[2]+d[4]/5)
end
end
