The first experiment of computer graphics

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69951068

77534803

50216979 midpoint draw Method

Simple metacode:

# Include <Gl/glut. h> # include <math. h> void midpointline (INT x0, int y0, int X1, int Y1) {float dx, Dy, M, X, Y, D, A, B; A = y0-Y1; B = x1-x0; dx = x1-x0; DY = Y1-y0; X = x0; y = y0; M = 1.0 * dy/dx; glbegin (gl_points); glvertex2f (x, y); glend (); If (M> = 0 & M <= 1) {d = 2 * A + B; while (x <= x1) {If (D> 0) // point {x ++; D + = 2 * A; glbegin (gl_points); glvertex2f (X, y); glend ();} else {x ++; y ++; D = d + 2 * A + 2 * B; glbegin (gl_points); glvertex2f (X, y); glend () ;}} else if (M> 1) {d = a + 2 * B; while (Y <= Y1) {If (D> 0) {d = d + 2 * A + 2 * B; y ++; glbegin (gl_points); glvertex2f (x, y); glend ();} else {d + = 2 * B; X ++; y ++; glbegin (gl_points); glvertex2f (x, y); glend ();}}} else if (M <= 0 & M> =-1) {d = 2 * A-B; while (x <= x1) {If (D> 0) {d = d + 2 * A-2 * B; X ++; glbegin (gl_points); glvertex2f (x, y); glend ();} else {d = d + 2 * A; X ++; y --; glbegin (gl_points); glvertex2f (x, y); glend ();}}} else {d = A-2 * B; while (Y> = Y1) {If (D> 0) {d = D-2 * A; X ++; y --; glbegin (gl_points); glvertex2f (x, y); glend ();} else {d = d + 2 * A-2 * B; y --; glbegin (gl_points ); glvertex2f (x, y); glend () ;}}} void changesize (glsizei W, glsizei h) {If (H = 0) H = 1; glviewport (0, 0, W, H); glmatrixmode (gl_projection); glloadidentity (); If (W <= h) {glortho (0.0f, 500366f, 0.0f, 500366f * H/W, 1.0f, -1.0f);} else {glortho (0.0f, 500366f * W/H, 0.0f, 500366f, 1.0f,-1.0f);} glmatrixmode (gl_modelview); glloadidentity ();} void Init () {glclearcolor (0.0f, 1.0f, 1.0f, 1.0f);} void renderscene () {glclear (gl_color_buffer_bit); glcolor3f (1.0, 0.0, 0.0); midpointline (100,250,250, 50); glflush ();} int main (INT argc, char * argv []) {gluinit (& argc, argv); gluinitdisplaymode (glu_rgb | glu_single ); valley createwindow ("line"); Init (); maid (100,100); fig (500,500); fig (renderscene); fig (changesize); fig (); Return 0 ;}

Dot line algorithm code:

# Include <Gl/glut. h> # include <math. h> void midpointline (INT x0, int y0, int X1, int Y1) {float dx, Dy, M, X, Y, D, A, B; A = y0-Y1; B = x1-x0; dx = x1-x0; DY = Y1-y0; X = x0; y = y0; M = 1.0 * dy/dx; glbegin (gl_points); glvertex2f (x, y); glend (); If (M> = 0 & M <= 1) {d = 2 * A + B; while (x <= x1) {If (D> 0) // point {x ++; D + = 2 * A; glbegin (gl_points); glvertex2f (X, y); glend ();} else {x ++; y ++; D = d + 2 * A + 2 * B; glbegin (gl_points); glvertex2f (X, y); glend () ;}} else if (M> 1) {d = a + 2 * B; while (Y <= Y1) {If (D> 0) {d = d + 2 * A + 2 * B; y ++; glbegin (gl_points); glvertex2f (x, y); glend ();} else {d + = 2 * B; X ++; y ++; glbegin (gl_points); glvertex2f (x, y); glend ();}}} else if (M <= 0 & M> =-1) {d = 2 * A-B; while (x <= x1) {If (D> 0) {d = d + 2 * A-2 * B; X ++; glbegin (gl_points); glvertex2f (x, y); glend ();} else {d = d + 2 * A; X ++; y --; glbegin (gl_points); glvertex2f (x, y); glend ();}}} else {d = A-2 * B; while (Y> = Y1) {If (D> 0) {d = D-2 * A; X ++; y --; glbegin (gl_points); glvertex2f (x, y); glend ();} else {d = d + 2 * A-2 * B; y --; glbegin (gl_points ); glvertex2f (x, y); glend () ;}}} void changesize (glsizei W, glsizei h) {If (H = 0) H = 1; glviewport (0, 0, W, H); glmatrixmode (gl_projection); glloadidentity (); If (W <= h) {glortho (0.0f, 500366f, 0.0f, 500366f * H/W, 1.0f, -1.0f);} else {glortho (0.0f, 500366f * W/H, 0.0f, 500366f, 1.0f,-1.0f);} glmatrixmode (gl_modelview); glloadidentity ();} void Init () {glclearcolor (0.0f, 1.0f, 1.0f, 1.0f);} void renderscene () {glclear (gl_color_buffer_bit); glcolor3f (1.0, 0.0, 0.0); midpointline (100,250,250, 50); glflush ();} int main (INT argc, char * argv []) {gluinit (& argc, argv); gluinitdisplaymode (glu_rgb | glu_single ); valley createwindow ("line"); Init (); maid (100,100); fig (500,500); fig (renderscene); fig (changesize); fig (); Return 0 ;}

　　

The first experiment of computer graphics