From 1aad8e5f9e8f5bf8bfb8e75b1d9483342ab8b0fa Mon Sep 17 00:00:00 2001
From: milang <milan.garnier@orange.fr>
Date: Sun, 1 Sep 2019 12:28:31 +0200
Subject: [PATCH] correct perspective deformation (this is quite slow, and I
 will turn `double` to `int` as soon as possible)

---
 libfxengine.a         | Bin 9664 -> 9696 bytes
 src/render/triangle.c |  41 ++++++++++++++++++++++++-----------------
 2 files changed, 24 insertions(+), 17 deletions(-)

diff --git a/libfxengine.a b/libfxengine.a
index 001a3dc5e82a91092b563351994f8bfb3339eaf9..850b3a591f6d034d72025ff2ccdb76830c3152fe 100644
GIT binary patch
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diff --git a/src/render/triangle.c b/src/render/triangle.c
index 7820c6d..85f4f34 100644
--- a/src/render/triangle.c
+++ b/src/render/triangle.c
@@ -18,8 +18,8 @@ void render_update(const uint32_t libprof_channel)
     // gestion du temps avec libprof
     if (prof_elapsed)
     {
-        prof_leave(0);
-        uint32_t frame_interval = prof_time(0);
+        prof_leave(libprof_channel);
+        uint32_t frame_interval = prof_time(libprof_channel);
         //sleep_us(0, MINIMUM_FRAME_DELAY-frame_interval);
         if (frame_interval<frame_interval_min)
             frame_interval_min = frame_interval;
@@ -31,14 +31,14 @@ void render_update(const uint32_t libprof_channel)
         prof_init(libprof_channel+1, 0);
     }
     //dupdate();
-    prof_clear(0);
-    prof_enter(0);
+    prof_clear(libprof_channel);
+    prof_enter(libprof_channel);
 
     render_zbuffer_clear();
 
     ///render_set(dh, dv, roulis, camera);
 
-    dclear(C_WHITE);
+    //dclear(C_WHITE);
 }
 
 /**
@@ -143,15 +143,15 @@ void render_display_triangle(const render_triangle * face)
         return;
 
     // incomplete clipping
-    if (face->s1->x < 0 && face->s2->x < 0 && face->s3->x < 0)
+    if (face->s1->x < 0  &&  face->s2->x < 0  &&  face->s3->x < 0)
         return;
-    if (face->s1->x >= render_width && face->s2->x >= render_width && face->s3->x >= render_width)
+    if (face->s1->x >= render_width  &&  face->s2->x >= render_width  &&  face->s3->x >= render_width)
         return;
-    if (face->s1->y < 0 && face->s2->y < 0 && face->s3->y < 0)
+    if (face->s1->y < 0  &&  face->s2->y < 0  &&  face->s3->y < 0)
         return;
-    if (face->s1->y >= render_height && face->s2->y >= render_height && face->s3->y >= render_height)
+    if (face->s1->y >= render_height  &&  face->s2->y >= render_height  &&  face->s3->y >= render_height)
         return;
-    if (face->s1->z <= 0 && face->s2->z <= 0 && face->s3->z <= 0)
+    if (face->s1->z  <=  0 && face->s2->z  <=  0 && face->s3->z  <=  0)
         return;
 
     line cotes[3];
@@ -184,7 +184,7 @@ void render_display_triangle(const render_triangle * face)
         }
         for (int32_t t=0;t<3;t++)
         {
-            if (line_get_x(y,&cotes[t],&tx2)&&tx1!=tx2)
+            if (line_get_x(y,&cotes[t],&tx2) && tx1!=tx2)
                 break;
         }
 
@@ -197,19 +197,26 @@ void render_display_triangle(const render_triangle * face)
             // calcul de vx, vy
             vx=(xcalc*fact_1-ycalc*fact_2); // 0 <vx< 10_000
             vy=(ycalc*fact_3-xcalc*fact_4); // idem
-            z=face->s1->z + (vx * zAB  +  vy * zAC) / 32768;
-            vx /= 32768;
-            vy /= 32768;
+            z=face->s1->z + (vx * zAB  +  vy * zAC) / 32768.0;
+            vx /= 32768.0;
+            vy /= 32768.0;
 
+            double vx2= ( vx/face->s2->z ) / ((1-vx)/face->s1->z + vx/face->s2->z);
+            double vy2= ( vy/face->s3->z ) / ((1-vy)/face->s1->z + vy/face->s3->z);
+            /* Perspective correction
             vx /= (double) face->s2->z / ((1 - vx) / face->s1->z + vx / (double) face->s2->z);
             vy /= (double) face->s3->z / ((1 - vy) / face->s1->z + vy / (double) face->s3->z);
-
+            */
             // Affichage du point
-            const uint8_t color = bitmap_get_pixel_r(face->texture, 8*vx, 8*vy);
+            const uint8_t color = bitmap_get_pixel_r(face->texture, face->texture->size_px_x * vx2,
+                                                                    face->texture->size_px_y * vy2);
 
-            if (color)
+            if (color >> 1)
+            {
+                //dpixel(x,y, C_BLACK);
                 if (render_zbuffer_set_px(x,y,z))
                     dpixel(x, y, 3 * (color % 2)); // 3* means cast to black and white, and vx,and vy casted between 0 and 7
+            }
         }
     }
 }